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The first week of the season is always a good time to see a reveal of what teams plan to do. While we guessed what the San Francisco 49ers would do all season, we were finally able to see what they thought about their roster.
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What were the most notable starting decisions?
5 notable starting decisions by San Francisco 49ers
Connor Colby at left guard
The biggest question all offseason was who would start at left guard. Connor Colby was the first person to get a chance, but the team moved him to right guard later in the preseason. However, that appeared to have just been a chance to give rookie Carver Willis a look with the starters. Willis did not win the job, and the team ended up going back to the second-year guard.
Jaden Dugger as the third linebacker
We knew that Dre Greenlaw would start next to Fred Warner. However, when a third linebacker came on the field, it was not clear what the 49ers would do. Luke Gifford had the job, but he has been injured all offseason. Rookie fifth-round pick Jaden Dugger stepped up and took the job. He saw a significant role in his rookie debut, playing the SAM.
Marques Sigle over Malik Mustapha
Mustapha has 22 starts in his first two NFL seasons, and he missed five games last year due to an ACL injury he suffered the year prior. When Mustapha is healthy, he has been viewed as a starter. He has not been fully healthy in training camp, but was active in Week 1. Still, he played special teams and came in for garbage-time work. Besides that, he was the backup to second-year safety Marques Sigle.
Whether Mustapha continues to back up Sigle will be worth watching.
Kaelon Black as RB2
The 49ers were supposed to have a running back competition between Black and second-year Jordan James in training camp. Both were hurt in training camp, so the battle felt unresolved. However, the team made James inactive, and Black had four more rushes than Christian McCaffrey. It is clear who the backup is.
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Keion White and CJ West started
Mykel Williams is on the PUP, and Alfred Collins is on the IR. To replace the first two picks in the 2025 NFL Draft, the 49ers called on White and West. West struggled, and rookies James Thompson and Gracen Halton flashed more. Will he continue to start?
Today’s best reads
- 5 49ers Who Need to Step Up in 2026
- 4 49ers Rookies Who Can Earn Larger Roles During the Season
- 49ers Rookie Power Rankings Heading Into Week 1
- The 5 Biggest Issues That Could Derail the 49ers in 2026
- 5 49ers Who Need to Step Up in Week 1 vs. Rams
This article was originally published on www.si.com/nfl/49ers/onsi as 5 Biggest 49ers Lineup Revelations From Week 1.
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This story was originally published September 11, 2026 at 10:00 AM.