SANTA CLARA -- Deforest Buckner has played more snaps this season than all but three NFL defensive linemen, the result of both the long stretches the 49ers defense has been on the field in 2016 and the fact that the rookie is hard to take out of the game.
For one, Buckner is accustomed to playing a high number of snaps. Last year at Oregon, he said 80- or 90-snap games were common for him and he ended up playing more defensive snaps than all but one Division I defender.
Buckner said he can tap his helmet at any point during a game, the signal that he needs a break, and the 49ers coaches will send a substitute from the sideline.
He just doesn't tap his helmet very often. Against the Patriots on Sunday, he played all but one of the team's 76 defensive snaps. The week before that in Arizona, he was on the field for 77 of San Francisco's 79 snaps.
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"When I'm really tired, I'm volunteering to come out. I tap my helmet," he said. "If they don't have anybody to come sub me out, I've got to be out there to kind of grind through it."
The 49ers began their season with a seemingly deep group of defensive lineman, but the position has thinned over time. Arik Armstead's season-ending shoulder injury means that Buckner's replacements on base downs are either Tony Jerod-Eddie or Mike Purcell, who is more of a nose tackle.
Buckner, meanwhile, has improved over the first 10 games. His three sacks -- though not impressive when compared to the league's top pass rushers -- lead all 49ers defensive linemen and put him in second place behind team leader Ahmad Brooks, who has 3 1/2.
"I think early in the year you saw Buck making a lot of plays in the run game, and then he was making a lot of exceptional effort plays and now he’s starting to get really close and affect the quarterback," defensive coordinator Jim O'Neil said this week. "The next step for him is just going to be to finish those plays. But he knows and we know that’s what he needs to do to be that three-down difference maker. So I really see him coming on."
O'Neil has said he's comfortable with Buckner playing 80 percent of the defensive snaps this year. The rookie's snap count, however, is much higher than that.
Buckner's 617 snaps trail only the New York Giants Jason Pierre-Paul (691) and Olivier Vernon (666) and the Saints Cameron Jordan (619). Buckner's count may be more remarkable than that of the three veterans ahead of him, however, not just because he's a rookie but because he missed a full game, Week 5 against Arizona, with a foot injury. Subtract that game and Buckner has played nearly 90 percent of the 49ers' defensive snaps.
Chip Kelly, an advocate of sports science, said the 49ers are keenly aware of everything from how many snaps their players play to how much distance they travel. As far as Buckner’s snap count?
“I think overall defensively, we just have to do a better job on third down and get him off the field and not play as many snaps,” he said.
Et cetera -- Kelly said cornerback Jimmie Ward (concussion) would take part in practice Thursday on a limited basis, which, barring a setback would put him on track to play Sunday against the Dolphins.
* Kelly said the 49ers will continue to monitor outside linebacker Aaron Lynch, who is recovering slowly from last month’s high-ankle sprain. Whether Lynch can play Sunday will be decided after Saturday’s practice or after Lynch warms up Sunday.
* The 49ers began their day a little earlier than normal -- at 7:15 a.m. -- so the players could leave in the afternoon and enjoy a Thanksgiving Day meal.