Now that we know Alex Mack has retired and won't play this season, let's project the 49ers' five starting offensive linemen for Week 1.
The 49ers had to have known all offseason Mack was going to retire, which means they're prepared to replace him. They must have the plan. And the plan can't be to start journeyman backup Jake Brendel at center.
Here's my best guess at who will start on the offensive line in the season opener:
Left tackle: Trent Williams. This is the one position that's set in stone.
Left guard: Aaron Banks. The 49ers spent a second-round pick on him last year, so they'll give him the first shot to start. But if he struggles, they probably will replace him with Colton McKivitz, who at least is solid.
Center: Daniel Brunskill. He started eight games at center for the 49ers in 2020 before they signed Mack, so it would make sense that the 49ers would move Brunskill back to center now that Mack has retired. Brunskill isn't a particularly good center, but he's serviceable and a veteran.
Right guard: Jaylon Moore. The 49ers drafted him in Round 5 last year and he played well during the preseason. He probably has a better chance to keep his job than Banks. He also could play right tackle if the 49ers feel rookie Spencer Burford is ready to start at right guard.
Right tackle: Mike McGlinchey. Unless he's still injured. In that case, Justin Skule or Jaylon Moore most likely would start at right guard.
More must-reads: