A breakdown of the Detroit Lions' 2018 free-agent signings:

Wesley Johnson, C

The Lions signed center Wesley Johnson, who was a starter with the Jets last season. Here’s a closer look at the signing:

Grade: C-. Johnson may have been a starter with the Jets last season at center, but he was also the lowest-graded center by Pro Football Focus in 2017 -- No. 35 of 35. So it’s tough to see if he’s an upgrade over last year’s center combination of Travis Swanson and Graham Glasgow (when Swanson was hurt).

What it means: Detroit is trying to bring in competition for its one vacant offensive line spot (either center or left guard, depending what the Lions choose to do with Graham Glasgow), and Johnson is that considering Detroit doesn’t appear to be interested in bringing back Swanson. He’ll likely compete with Glasgow and Leo Koloamatangi for the starting center role and a combination of Joe Dahl and Kenny Wiggins for the left guard spot. Wiggins and Glasgow should have roster spots. The rest will likely be shooting for one or two interior line spots. This could also lock up Detroit’s offensive line prospects, but a draft pick could be added -- and if it is an early enough selection, could set most of Detroit’s offensive line roster (barring injuries) before training camp starts.

What’s the risk: Like with a lot of Detroit’s pickups, it’s a salary thing. As long as there isn’t much tied into Johnson’s contract, then there’s no risk. If there’s a minimal signing bonus attached, that’s OK, too. But otherwise, bringing in a player who has starting experience and a fifth-year veteran from Vanderbilt has little downside and the potential for being a bargain if he plays well. If the contract is surprisingly high -- he was on a second-round tender to the Jets last year worth $2.746 million -- then that’s a concern. But this was not a tender deal, and he’s signing fairly deep into free agency, so it’d be stunning to see a contract that high.

Levine Toilolo, TE

The Lions signed tight end Levine Toilolo, who has been with the Atlanta Falcons the last five seasons. Here’s a closer look at the signing:

Grade: B. This seems like a depth deal with the potential to push for a spot on the roster. Detroit could still have used some veteran presence in the tight end room given the lack of experience other than Luke Willson. This is it.

What it means: Not much. Toilolo is a big target for Matthew Stafford and potentially a blocking tight end. He has played in all but one game over his five years with Atlanta, but never had more than 31 catches in a season (2014) or 264 yards (2016). Those 31 catches were an anomaly in his career, as he has had 43 catches in the other four seasons combined. This is more of a cheap, veteran move for Detroit to pick up some experience and give a guy a shot to make the roster. The Lions have done this the past few years with Matt Asiata, Geoff Schwartz and others. This move also should not prevent the Lions from drafting a tight end since both Willson and Toilolo are on one-year deals. With that in mind, Detroit still needs to plan for its future at the position, whether that’s Michael Roberts or another player or a combination of both.

What’s the risk: Not much really unless his contract is bigger than anticipated. Toilolo has experience and durability so he gives the Lions another option at a position that is lacking both of those things other than Willson – and Willson has struggled with injuries. If his contract is a veteran minimum deal or close to it, there is very, very little risk involved here for Detroit.

Jonathan Freeny, LB

The Lions signed linebacker Jonathan Freeny, who has been with four teams during his career, including the New England Patriots. Here’s a closer look at the signing:

Grade: C. This is a signing that seemed like a match for a while now considering Freeny’s most extensive time in the NFL came with New England under Matt Patricia. Freeny is likely to be more of a depth linebacker in Detroit, perhaps competing with Nick Bellore and Steve Longa for a reserve/special-teams role.

What it means: This could be a signing to help create the culture Patricia wants to build in the locker room. Patricia has experience with Freeny in New England, and the linebacker is one of the few free-agent signees -- along with Tavon Wilson and LeGarrette Blount -- to know Patricia fairly well. There’s a chance Freeny could compete for a starting spot in a 3-4 defense (the 4-3 parings would seem to be locked in with Jarrad Davis, Devon Kennard and either Christian Jones or Jalen Reeves-Maybin), but it seems like he would be more of a special-teams/reserve player.

What’s the risk: Unless the Lions gave him a surprisingly large deal, not much. If Detroit brought him in for the minimum or close to it, it’s a low-risk, potentially high-reward deal that could be extremely beneficial if Freeny were to win a starter’s or valuable reserve’s role. If not, unless the Lions overpaid for him, it’s a move that could help build the culture in Detroit. Freeny is a team player who has versatility at linebacker. He’s basically the type of player Patricia and general manager Bob Quinn want.

Sylvester Williams, DT

The Lions signed Williams, who was cut by Tennessee earlier this year after completing just one season of a three-year contract. Here's a closer look at the signing:

Grade: B-minus. Detroit needed to add experience on the interior of its defensive line and had to improve its run defense after departures in free agency and struggles in the second half of last season. Williams should help, but he doesn't come without risk.

What it means: The Lions had to find a replacement for Haloti Ngata, who left for Philadelphia last week in free agency. In the 6-foot-3, 313-pounds Williams, they get a space-eater in the middle who is good against the run. It also could help solve Detroit's pass-rush woes if Williams can create enough attention in the middle of the line to help free up defensive ends Ezekiel Ansah and Kerry Hyder. Williams, a 2013 first-round pick, has Super Bowl experience with the Denver Broncos and understands what it takes to be part of a top-rated defense. It's a signing that could be an improvement over what Detroit had in Ngata and makes the Lions younger at the position with the 29-year-old Williams.

What’s the risk: This will be Williams' third team in three seasons, having gone from Denver in 2016 to Tennessee last season and now Detroit. That should be a concern. He's also not a great pass-rusher, so the Lions still are going to have to find some help in that area. How big of a risk this deal is will depend on the numbers, particularly with other defensive linemen (particularly Johnathan Hankins) still on the market.

Luke Willson, TE

The Lions signed Willson, who spent the first five seasons of his career with the Seattle Seahawks. Here’s a closer look at the signing:

Grade: C. This is a fairly average signing but fills the veteran tight end role Darren Fells vacated when he left for Cleveland. Willson might be a better receiver than Fells, but he’s not nearly the receiver or caliber of tight end Eric Ebron was. The Lions cut Ebron a week ago and he landed with Indianapolis. So part of this grade has to do with the players the Lions lost as much as Willson coming in.

What it means: It’s a homecoming of sorts for Willson, who grew up in La Salle, Ontario. He has 89 career catches for 1,129 yards and 11 touchdowns in his five seasons, but he’s unlikely to be a playmaker considering his career highs are 22 catches and 362 yards in a season (both in 2014). The Lions are still going to be in the market for a tight end -- likely now in the draft, where they will try to find a replacement for Ebron, who had his issues but also showed flashes of being a playmaker.

What’s the risk: There isn’t much of one, mostly because of what was still out there on the tight end market. A couple of the top available tight ends signed with division rivals (Jimmy Graham to Green Bay, Trey Burton to Chicago), and the Lions let go of Ebron, who was the best tight end left until he signed with Indianapolis. If Willson’s blocking becomes an issue, this signing might not look great. But if he can show more as a receiver than he did in Seattle, then it could be a bonus. That’s the big question: Could his role with the Seahawks have been expanded or is this what he is as a player -- a guy who fills a role but won’t be a big-time difference-maker?

LeGarrette Blount, RB

The Detroit Lions signed veteran running back LeGarrette Blount, who was with Philadelphia last year. Here’s a closer look at the signing:

Grade: B+. This is a signing the Lions needed to have. Detroit had the worst run game in the NFL last year and struggled particularly in short-yardage situations. Blount gives them a veteran runner who knows how to pick up short yards.

What it means: General manager Bob Quinn said in January he was going to add at least one back to the running back corps for 2018. That it’s Blount, who has experience with both Quinn and new head coach Matt Patricia, is not surprising. The Lions' need for this and desire for it was clear throughout the week, with four veteran backs visiting Detroit. Blount was the last visit, on Friday, and the player the team chose to go with. He’ll have an immediate role in the offense and should push Zach Zenner, Ameer Abdullah and Tion Green for reps. He shouldn’t be Detroit’s lead back but should have a strong complementary role. This also should not preclude Detroit from drafting a running back early in April’s draft as the Lions need a younger back to start working with to build a run game around for the future since Blount turns 32 in December.

What’s the risk: Running backs over age 30 are always a concern, but Blount has been consistent throughout his career. He’s gained over 4.0 yards per carry in four of the past five seasons, including 4.4 yards last year for Philadelphia. But when a back starts to fall away, it usually happens quickly, and that’s always going to be a worry.

Zach Zenner, RB

The Lions re-signed running back Zach Zenner, a reserve back for Detroit the past three seasons who was not tendered earlier this year. Here's a closer look at the signing:

Grade: C. Zenner was mostly used as a reserve running back throughout his first three seasons with the Lions. Detroit chose not to tender him -- $1.9 million for a possible No. 4 running back doesn't make sense -- but always indicated it would like to bring him back.

What it means: This won't change any of the Lions' other running back plans, from bringing in an older veteran to drafting a back this year. Zenner will compete for the No. 3 or No. 4 running back during the preseason. If the Lions look at a running back by committee situation this season, he could end up on the roster. Detroit knows what it's getting with him and knows he is responsible enough to handle it.

What's the risk: If the Lions are banking on him to play a larger role in the run game than he should have, then that would be a problem. As long as Detroit general manager Bob Quinn does what he said he would do, which is bring in at least one new back (if not two), then there's no risk to re-signing Zenner, who is a low-risk type of player and a good locker room presence.

Kenny Wiggins, OL

The Lions signed offensive lineman Kenny Wiggins, who started 16 games at right guard for the Los Angeles Chargers last year. Here’s a closer look at the signing:

Grade: C. If you’re asking, "Who?", you’re not alone, but that’s not the worst thing for an offensive lineman. Wiggins began his career on the practice squads of Baltimore and San Francisco before heading to Southern California, first on the practice squad and then, after being out of football for most of 2014, was part of the Chargers the past three seasons. This is not an impact signing off the top, though.

What it means: The 29-year-old is likely to be part of a competition with Joe Dahl to provide depth on the interior line or potentially a starter at guard if Graham Glasgow moves over to center. Wiggins played left guard and right guard, so he has some position flexibility, and he played under new offensive-line coach Jeff Davidson in 2016. So there should be some familiarity with what the Lions are going to run up front.

What’s the risk: If it’s a low-money deal, there’s not much risk involved. If the Lions are hoping Wiggins becomes the team’s left guard, there should be some concern because he’s only had one full season as a starter on the offensive line. But if he’s competing for depth and to try and become a starter, then it’s not a bad signing since he has some experience. This will all come down to the money involved.

DeShawn Shead, CB

The Lions signed cornerback DeShawn Shead, who has spent his entire career in Seattle. Here's a closer look at the signing:

Grade: B-minus. Shead isn't a ball-hawk like Darius Slay. He has only two career interceptions, but he has experience playing across from a Pro Bowler from his time in Seattle with Richard Sherman. Now he'll do that with the Lions and Slay.

What it means: Nevin Lawson, who officially re-signed earlier Wednesday, will have competition to start at corner on the outside. That was already the case with last year's second-round pick, Teez Tabor, but Shead has more experience than Tabor. At 6-foot-2, Shead has height that no other Lions corner can match. He also has special teams experience, with 19 career special teams tackles, so he could be an option there. If he beats out Lawson on the outside, that'll allow the Lions to move Lawson in the middle.

What's the risk: Shead only has a couple of seasons of being a full-time defensive player and hasn't played a defensive snap since 2016, when he had 80 tackles in 15 games. Shead had an ACL injury in January 2017 so there's going to be some question as to how he moves after missing most of last season (he returned for a couple games, but didn't play much on defense). The Lions mitigated some risk by signing him to a one-year deal -- a deal similar to the one they gave D.J. Hayden last season. ESPN Insider Adam Schefter is reporting it's a one-year, $3.5 million deal that can be up to $6.5 million with incentives.

Nick Bellore, LB

The Lions re-signed Bellore, who was with the team last season as a linebacker/fullback/special teams ace. Here's a closer look:

Grade: C. He's an average signing in the scheme of things, but a good move from a depth perspective.

What it means: Not much from a starter's perspective, but he's a valuable backup who has been a starter and can play linebacker in a pinch. He's more valuable as a core special teams player -- along with on-the-roster linebacker Steve Longa -- and has shown versatility as a fullback for Detroit. This is a depth deal and the type of player Matt Patricia and Bob Quinn have shown they like to have on their roster. This type of move is the one that Quinn has consistently made throughout his time as general manager.

What's the risk: The Lions have injuries at linebacker and Bellore is asked to do more than spot duty as a linebacker. That's where Detroit can get into trouble. Otherwise, the Lions know what they are getting in Bellore, saw it last year and likely expect more of the same on what is probably a low-end deal this year.

Nevin Lawson, CB

The Lions are re-sigining Lawson, who had spent the first four years of his career with the club, to a two-year deal worth up to $10.3 million, according to a source (first reported by CBS Sports). Here's a closer look at the signing:

Grade: B-minus. Detroit missed out on some potential bigger names at corner -- Malcolm Butler being the most obvious -- but Lawson knows the personnel. He is comfortable playing next to Detroit's safeties and came in at a much more reasonable price for a player who is going to compete to be a starter -- not a sure-fire one -- as the Lions work with younger players to get them ready for the future.

What it means: The Lions secondary is going to look very similar to the group it had last year -- for good and for bad. Detroit brought back two free-agent pieces Tuesday in safety Tavon Wilson and Lawson. This could mean a lot of competition for the starting corner slots opposite Darius Slay. Lawson will compete against Teez Tabor for the outside spot and Jamal Agnew in the slot. It shows Detroit has confidence in its secondary group and wants to focus more on the front seven, although it's possible this move came after Detroit lost out on bigger names who were out of its price range. Lawson has flexibility, able to play either outside or in the slot, so he should compete for a starting role at both places. At the price, though, it makes sense.

What's the risk: Lawson is an underrated player whose play gets undervalued because he's opposite an All-Pro in Slay and in the same defensive backfield as Pro Bowler Glover Quin. The concern would be that he plays more like he did in 2017 than he did in 2016, when he started to emerge as a strong cornerback. His 2017 season was rough and he ended up in a platoon by the middle of the year. He's not going to be a ball-hawk -- he has yet to have an interception in his career -- but he's a guy who the Lions can rely on.

Devon Kennard, LB

The Lions agreed to terms with Kennard on a three-year, $18.75 million deal, which was confirmed by ESPN's Jordan Raanan and first reported by NFL Network. Kennard has been a linebacker for the New York Giants the past four seasons. Here's a closer look at the signing:

Grade: B-minus: He doesn't have the numbers that you'd want to see out of a pass-rusher you're signing in free agency, but he should get more of a chance to be a full-time pass-rusher in Detroit. He's also a player who can be versatile for new coach Matt Patricia's defense.

What it means: Kennard is a young player who has good size and can come in and play right away. He's not a big-time pass-rusher, and there's more of a chance he ends up in a non-pass-rushing role in Detroit's new defense. He started 35 games over his four seasons with the Giants and had 9.5 sacks. Detroit needed to add at least one starting-caliber linebacker to go along with Jarrad Davis and potentially Jalen Reeves-Maybin, and Kennard could be it. Kennard's signing could mean the departure of one or both of Paul Worrilow and Tahir Whitehead, the Lions' two current linebackers who are scheduled to become free agents. He's a better pass-rusher than either of those players, but Whitehead might have been the better run-stopper, while his coverage skills remain in question.

What's the risk: The question is whether Kennard is better than what the Lions already had in Whitehead -- if that's the role he ends up filling. It's unclear whether there's a definitive answer, and Whitehead is a familiar face with a bunch of connections in Detroit's locker room. Kennard has also played all 16 games just once in his four-year career (although he's been in 31 of 32 games the past two seasons).

Christian Jones, LB

The Lions agreed to terms with Jones, who had been a linebacker for the Chicago Bears the past four seasons. Here's a closer look at the signing:

Grade: B. Jones can play inside or outside linebacker -- again, giving the Lions a versatile piece they can use multiple places. He's also a guy who can play special teams if necessary, which would be key if he loses out on a job to second-year pro Jalen Reeves-Maybin at some point. This is a smart value signing.

What it means: Between the agreed-to terms with Kennard and now a two-year deal for Jones, Detroit's linebackers are going to have a different look this season. Jones isn't much of a pass-rusher, with four career sacks, but he has seven career passes defended. Jones is the type of linebacker new coach Matt Patricia could want in his defense. It is reasonable to think, though, that Jones could end up being a depth linebacker in some cases if Reeves-Maybin shows he's ready for a larger role in 2018. That Jones has significant special-teams experience (26 tackles in his four years), could help. He had some of his better games against the Lions, including an 11-tackle, one-sack performance as a rookie in 2014 along with eight tackles and a sack in November.

What's the risk: Tough to say. He's been reliable and healthy throughout his career and has played multiple positions. He might be the type of linebacker who gets a lot of work in weeks Detroit wants to play a 3-4, and then situationally, depending on the progression of other players. He's played in a 4-3 and a 3-4 in his career, so he's versatile. There's not a ton of risk here other than the usual risk bringing a new player into a new program and locker room.

Tavon Wilson, S

The Lions re-signed Wilson, who had been the team's starting strong safety the past two seasons. Here's a closer look at the signing:

Grade: B. This is a fair deal for the Lions and for Wilson, who is coming off an injury but had settled into the strong safety role. It also gives stability at the position and brings back a core of the Lions' defensive backfield.

What it means: First, this gives Detroit flexibility when it comes to how the franchise uses Quandre Diggs, who moved from nickel to safety after Wilson's season-ending shoulder injury. Diggs thrived in the role and now Patricia has some room to maneuver with those three players. Wilson can be an in-the-box safety who is a hard-hitter -- part of what won him the job in 2016 over Rafael Bush. This could also allow the Lions to move Diggs into the box in coverage for three-safety packages or nickel looks, depending on the opponent. Wilson is also a good special-teams player who has familiarity with the New England system and with Patricia. Patricia was Wilson's defensive coordinator his entire time in New England.

What's the risk: The biggest risk is Wilson coming back from the shoulder injury that plagued him throughout 2017 before ending his season on Thanksgiving. How he responds to that will be the biggest question out there, but otherwise this is a fairly low-risk move. Wilson has familiarity with the rest of the defensive backfield, is looked at along with Glover Quin as a leader and knows what Patricia is going to want to run. At the price -- two years, $7 million according to Adam Schefter -- it's an economical deal that makes sense.