SANTA CLARA, Calif. -- With the addition of veteran Jonathan Cooper, the San Francisco 49ers have three former first-round picks set to compete for two starting guard jobs on their offensive line.

Cooper, who signed a one-year deal with the Niners on March 21, is joined by Laken Tomlinson and Joshua Garnett as former first-rounders aiming to win starting spots in 2018.

At last week's NFL owners meetings, Niners coach Kyle Shanahan said the early plan is for Tomlinson to continue working on the left side, with Cooper getting first crack on the right side as Garnett works in at both spots on his way back from a knee injury.

"One thing about guard is, you only have so many guys on your roster so we'll see how the starting two guys end up," Shanahan said. "They've got to be able to play both. We practice everybody at every spot. Once people do end up becoming the for-sure starter or the competition is over, then you'll leave them at one spot, but you're always mixing around because you can only dress a certain amount on game day and you've got to be very versatile."

If one were to look solely at the draft status of those three guards, the easy conclusion would be that the Niners are set at the position. The reality, however, is far different. Of that trio, only Garnett is an original draft pick of the Niners, taken No. 28 overall in 2016. Tomlinson came to the Niners in a trade just before the start of last season after entering the league as the No. 28 pick in the 2015 draft by the Detroit Lions.

But none of the three was drafted by the current regime of Shanahan and general manager John Lynch. Further, of the three, only Cooper profiles as a natural fit in Shanahan's outside-zone-heavy offense. That system requires guards to have the speed and athleticism to get out in space and block at the second level. Last season, the 49ers allowed 43 sacks and averaged just 3.92 yards per carry between the tackles, 22nd in the league.

All of which means that the Niners might not be out of the market for guard help when it comes to the NFL draft. And for as long of a shot as it might be that he falls, we can't rule out a match between San Francisco and Notre Dame guard Quenton Nelson should he tumble to No. 9.

Widely regarded as one of the top three-to-five players in the draft regardless of position, Nelson is projected to be off the board before then. But in Nelson's case, the positional caveat can be tossed aside because his position is very much a factor in how he'll be valued. Traditionally, the only offensive linemen to go in the top 10, let alone the top five, are tackles.

Since 1988, only three guards -- including Cooper -- have gone in the top 10. Nelson will likely be No. 4 and for good reason.

A unanimous All-American as a junior, Nelson was the Fighting Irish's most valuable player in 2017. He started 36 games for Notre Dame over the past three seasons and earned a reputation for his strength, athleticism and nasty streak at 6-foot-5, 325 pounds. Nelson bench-pressed 225 pounds 35 times at the scouting combine, tied for second-most among offensive linemen.

From the time Nelson was a child, he looked the part of a future professional football player. Before each season of Pop Warner football, Nelson would have to lose 20 pounds just to meet the weight requirement to play against kids two or three years older than him. To build toughness, Nelson often had to overcome his own family to achieve success in sports. With parents who were each the youngest of six kids, Nelson eventually became the youngest out of 39 nieces and nephews.

Nelson refined his athletic abilities on a basketball court, as a goalie in soccer and, of course, on the football field. His former strength coach once referred to Nelson as a "balletic grizzly bear" with a "bizarre blend of grace and power."

Add it all up and you have one of the most dominant guard prospects to enter the NFL draft, one who believes he belongs in such company.

"I think I should be talked [about] in that regard, the top-five conversation, because you have guys that are dominating the NFL right now in Aaron Donald and Geno Atkins, Fletcher Cox, that have just been working on interior guys; you need guys to stop them, and I think I’m one of those guys," Nelson said. "You talk to quarterbacks, and they say if a D-end gets on the edge, that’s fine, they can step up in the pocket and they can throw; a lot of quarterbacks if given the opportunity can do that. That’s what I give is a pocket to step up in, and I think I also help the offense establish the run through my nastiness -- and establishing the run also opens up the passing game, so I think it’s a good choice."

Whether Nelson would be a good choice for the 49ers doesn't seem like much of a debate, though some will compare his size to the smaller, lighter interior linemen on the roster and ask if he'd be best served in Shanahan's offense. That's too simplistic of a way to look at it, though. Shanahan's scheme isn't as much about size as it is athleticism.

While Nelson could always trim down some, a big part of his appeal is his combination of size and athleticism. If the Niners landed Nelson, he'd instantly be their most athletic interior lineman based on his performance at the combine. Nelson didn't run the 40 because of a hamstring tweak, but he still finished among the top offensive linemen in the three-cone drill and 20-yard shuttle. In a division with the likes of the Rams' Donald and Ndamukong Suh, Nelson would be a welcome addition.

Chances are, Nelson will be long gone before the 49ers make their first-round selection and they'll have to find help at guard at some other point in the draft. But if he somehow slips to their spot, the Niners shouldn't have a problem making Nelson the fourth first-round guard on the roster.