On Thursday night, the San Francisco 49ers host the Los Angeles Chargers in Week 4 of the 2019 NFL preseason. Star players like quarterback Jimmy Garoppolo and defensive tackle DeForest Buckner won't see the field in the team's fourth preseason game, nor will key starters tight end George Kittle and defensive end Dee Ford, who recently returned to practice but will sit out the Niners' final exhibition matchup of 2019.

However, the state of the 49ers' final roster remains in flux, and with 53-man roster cuts looming on Saturday, Thursday's matchup with the Chargers will determine the fate of a number of roster hopefuls. Many of these players were on the outside looking in when the week began. But thanks to a handful of recent injuries, along with a surprising mid-week release of a potential starter, the following three players will have the opportunity to break the roster bubble with strong performances on Thursday.

3. RB Jeff Wilson

49ers second-year running back Jeff Wilson stepped in at the end of the 2018 season when injuries depleted San Francisco's backfield. Wilson performed admirably during his shortened rookie year, but he entered training camp near the bottom of the running back depth chart for the second consecutive season.

However, during a radio interview on Wednesday, 49ers general manager John Lynch disclosed running back Jerick McKinnon suffered a setback during his recovery from a knee injury he sustained last year. Lynch described the situation as “not encouraging” for McKinnon, but it could open the door for Wilson if the 49ers are forced to place their 2018 free-agent acquisition on Injured Reserve to start the season.

The 49ers already have three running backs on the roster, as well as fullback Kyle Juszczyk, but Wilson's tough running style differentiates himself from the other backs on the roster. There's nothing impressive about his 3.7 yards-per-carry average over the preseason, or his longest rush of just nine yards, which ranks last among the team's six running backs. But after failing to score a touchdown as a rookie, Wilson developed a nose for the end zone this preseason, scoring three of the team's four rushing touchdowns.

If Wilson is able to add to his touchdown total on Thursday, while continuing to run with purpose, he could find his way onto the roster to start the season.

2. LB Azeez Al-Shaair

Inside linebacker Azeez Al-Shaair began training camp as a long shot to make the 49ers roster, given his undrafted status and a 2018 knee injury that kept him out of offseason team activities (OTAs). But from the moment the former Florida Atlantic Owl put his pads on this preseason, he's played like a prospect with a bright NFL future.

Al-Shaair's strongest traits are his ability to seek out the ball carrier and his tackling skills, which is understandable given that he holds the FAU record for career tackles despite missing much of his senior year after tearing his ACL and MCL in the sixth game of the season.

It's evident that 49ers head coach Kyle Shanahan and defensive coordinator Robert Saleh recognize Al-Shaair's long-term potential. After a pair of strong performances to start the preseason, Al-Shaair ran with the second team instead of San Francisco's third-stringers last week. The former captain of his college squad played the important MIKE linebacker role, which was previously manned by veteran inside linebacker David Mayo. Over the course of the preseason, Mayo has appeared better suited for special-teams duties than a prominent role on defense, and could be expendable given the number of talented special-teamers on the roster.

Al-Shaair received another piece of positive news on Tuesday, as the 49ers officially released fellow linebacker Malcolm Smith, who was in competition for the team's starting SAM linebacker job. With another linebacker out of the running for a roster spot, the rookie doesn't need to be perfect on Thursday to make the roster, particularly since WILL linebacker Kwon Alexander could fill in at the MIKE position in a pinch.

If Al-Shaair can make a few flash plays, it may be enough for the 49ers to keep the raw-but-talented linebacker around for the 2019 season.

1. WR Kendrick Bourne

The third former undrafted free agent on this list, wide receiver Kendrick Bourne. led the San Francisco 49ers with 487 receiving yards in 2018, but is fighting for a roster spot in 2019. Lynch and Shanahan made significant moves at the position over the offseason, adding veteran wide receiver Jordan Matthews in free agency and a pair of wideouts on Day 2 of the 2019 NFL Draft.

Bourne's roster chances dwindled early in camp when third-year receiver Trent Taylor quickly demonstrated he was fully recovered from the back injury that hampered him last season — but a broken bone in Taylor's foot will now sideline the wideout for the first few weeks of the season.

In the 49ers' first preseason game, rookie wide receiver Jalen Hurd looked like he was ready for regular season action, as the converted college running back hauled in a pair of touchdown receptions. However, Hurd hasn't seen the field since his breakout performance, as a back injury has kept him out of action, and now threatens his availability for Week 1 of the regular season.

Meanwhile, Bourne has remained healthy and has participated in every game, amassing five receptions for 66 yards and a touchdown. Fellow receivers Richie James and Matthews have outplayed Bourne over the team's first three preseason games, but the third-year player's ability to stay on the field has kept him in the roster conversation.

Bourne should see extensive action in Week 4 of the preseason, and a strong showing could help him defeat the odds once again by propelling the receiver — and Shanahan favorite — onto the 49ers' final 53-man roster for the third straight season.