COSTA MESA, Calif. -- Nasir Adderley read the criticism on social media last season regarding why it took so long for him to recover from what was initially reported as a lingering hamstring strain.

"I feel like people thought it was a normal hamstring strain, and people assumed I could have been back sooner than I could have been," Adderley said. "But if anybody really knows me, they would have known that I would have been out there.

"I just remained cool. I know myself better than anybody. I know who I am as a man, so what's the point? I just take it on the chin. ... People are going to have opinions. At the end of the day, I just keep moving forward and just go out there to prove everybody wrong."

A second-round selection by the Los Angeles Chargers last April, the Delaware product was expected to come in and compete for the starting free safety job next to All-Pro strong safety Derwin James.

Instead, Adderley limped through his rookie season due to an injury he suffered during his pro day in March that progressively got worse. A four-year starter at Delaware, Adderley didn't miss a game in college, playing in 45 straight contests for the Blue Hens.

"Originally, everybody thought it was a normal hamstring strain, and I did too," Adderley said. "But it was a lot more severe than that, and it was kind of frustrating because it was involving my tendon and not an actual muscle belly.

"So it was a lot of stuff to figure out, and we finally figured out what it was. I got good rehab and stuff, so I feel better than I ever have, even before my senior year. ... I mean, it was really hard. I couldn't even squat or bend my knee after the [Week 4] Miami game."

Adderley played just 10 snaps defensively and 51 on special teams in four games at the start of the season. The Chargers placed Adderley on season-ending injured reserve during Week 8.

"He needs to get healthy, No. 1," Chargers general manager Tom Telesco said. "That's what this offseason is about. He's already had a number of weeks and months to get a head start on that. As he moves into the offseason, he's going to be a defensive back. It could be safety, it could be some nickel corner, it could be corner. We'll kind of see.

"The good thing in his brief amount of time that we saw him in the preseason and a little bit in the regular season, I feel good that he can play in this league. But we need to get him out there. He has some instincts, some quick-twitch. He'll hit. He has a good feel for the game, but he's got to get healthy, then get out there and start competing for time."

When Adderley saw the field, he flashed. Specifically, he corralled an interception and had three pass breakups in the final preseason game against the San Francisco 49ers.

Adderley's main goal this offseason is to get fully healthy and earn a role defensively, possibly as a nickel defender or third safety. The Chargers could use someone with Adderley's versatile skill set to slow down Patrick Mahomes and the defending Super Bowl champion Kansas City Chiefs.

Kansas City led the NFL with 21 touchdowns of at least 20 yards from scrimmage during the regular season. The Chargers struggled to get off the field on third down defensively, finishing No. 29 in the NFL in third-down conversion rate (45.1%).

Adderley's innate ability to close on the ball and make tackles in open space could help the Chargers limit explosive plays.

"I want to be someone that they can move around, because I feel like I have the ability -- whether it's at free safety, dime, nickel or corner -- whatever it is, even looking at guys like Jaylen Watkins or Adrian Phillips, I want to reach that level," Adderley said. "Be mentally sound at all those positions and physically make sure my body is able to do those different positions."

Adderley said he will stay in Southern California and train at the Chargers' facility. He looks forward to getting on-field reps once offseason training begins in April; but mentally, he said he feels like he has made strides.

"Just watching film, watching the game and understanding what we're trying to do a whole, not just my individual position, it's helped me out tremendously," Adderley said. "And it's another reason why I feel like I'll be able to be moved around a lot. I'm getting an understanding of what we're trying to do as a whole unit."

Adderley, who started running in December, said he is excited for the offseason so he can begin training the way he wants.

"He got down [on himself] a little bit," Chargers head coach Anthony Lynn said. "I don't believe he's ever been hurt before. Sometimes kids don't know how to handle that, so you've got to keep encouraging him and just let him know that he's not letting the team down by not being there. He's got to get himself right, get healthy, and we know he can make plays."