The 49ers close out their preseason schedule Thursday in San Diego in a game that means little for most of the roster. We know what it means for Colin Kaepernick, who will face plenty of scrutiny for his stance on the national anthem. Most of the starters are likely to sit, including Blaine Gabbert.

But a few non-quarterbacks have plenty on the line, including notable players on the roster bubble (we projected the final 53-man roster here).

Here are six non-quarterbacks we’ll be watching closely Thursday night:

WR DeAndre Smelter

Smelter returned to practice this week after missing the first three games with a hamstring strain. Smelter, of course, has not played in an NFL game after missing his rookie season recovering from an ACL tear. With Eric Rogers (ACL) done for the season and Jerome Simpson released, Smelter and undrafted rookie Devon Cajuste are San Francisco’s biggest receivers remaining. The 49ers would love a chance to evaluate Smelter after extended snaps against the Chargers. Otherwise, it’s likely he spends the season on the practice squad trying to get his legs back underneath him, if he doesn’t wind up on an injury list.

OL Marcus Martin

The 49ers already moved one of their third-round picks from 2014 when they traded Brandon Thomas to the Lions for receiver Jeremy Kerley. Martin, still just 22, hasn’t done much to solidify his roster spot playing center on the second team offensive line. San Francisco might consider keeping others (more later) to provide depth behind the starting five. When a center is drafted in the third round, he’s expected to become a starter quickly. And Martin didn’t live up to those expectations in his first two seasons, nor has he shown significant improvement entering his third year. The 49ers added two guards in the offseason – Zane Beadles and Joshua Garnett – limiting Martin’s value to San Francisco.

LB Gerald Hodges

Once the favorite to start next to NaVorro Bowman, Hodges has struggled to digest defensive coordinator Jim O’Neil’s scheme. He was the culprit on a bad run fit on C.J. Anderson’s 19-yard touchdown run in the second preseason game and hasn’t flashed the consistency needed to nail down the starting job. That’s allowed Ray-Ray Armstrong to look like a favorite for a roster spot while Michael Wilhoite looks like the more dependable and experienced option next to Bowman. Hodges could use a good preseason performance to help nail down a spot on the 53 with Nick Bellore out with a knee injury.

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OL Fahn Cooper and OL Colin Kelly

With the release of Erik Pears last week, the 49ers’ ‘swing’ tackle job is up for grabs. Kelly has gotten the bulk of the second-team reps at left tackle behind Joe Staley since Pears’ release, while Cooper could play all four tackle and guard positions, giving him a good argument to make the roster as a reserve. With Anthony Davis transitioning to guard and Trent Brown working only on the right side, the 49ers seem apprehensive about moving either to the left side if Staley were to suffer an injury. Kelly is unique because he plays tackle and center, which could allow the 49ers to move on from Martin. Beadles has also been cross-trained at center in recent practices.

OLB Marcus Rush

Rush is tied for second in the NFL with four sacks in the preseason, half a sack behind the leader Justin Trattou of the Vikings. Rush’s chief competition for a roster spot, Corey Lemonier, has zero. But there’s a chance the 49ers keep just three outside linebackers – Ahmad Brooks, Eli Harold and Tank Carradine – with Aaron Lynch suspended for the first four games of the regular season. San Francisco could afford to keep three because of the versatility of their defensive linemen and O’Neil’s scheme. In sub packages, which the 49ers will be in two-thirds of the time, Arik Armstead, DeForest Buckner, Ronald Blair and Tony Jerod-Eddie could be used to rush the passer from the edges. But another good showing from Rush could ensure his chances at making it. Plus, he’s a good special teams player.