Marcus Martin is one of four 49ers who has been ruled out of Sunday’s game against the Lions, raising the prospect that rookie Trent Brown will make his first-ever NFL start.
Martin, who started the most recent game at right guard, suffered a concussion in the third quarter. When he left the game, Erik Pears moved from tackle to guard and Brown, a seventh-round pick, played most of the second half at tackle.
Brown played well mostly working against Cincinnati defensive end Carlos Dunlap.
Shaun Draughn also has been ruled out. That means the 49ers have just two healthy runners, Kendall Gaskins and DuJuan Harris, unless they elevate Jarryd Hayne from the practice squad Saturday.
Out: LG Alex Boone (knee), RB Shaun Draughn (knee), OL Marcus Martin (concussion), ILB Michael Wilhoite (ankle)
Probable: DT Arik Armstead (shoulder), ILB NaVorro Bowman (shoulder/finger), CB Tramaine Brock (hamstring), OLB Ahmad Brooks (shoulder/back), DT Quinton Dial (shoulder), OLB Eli Harold (shoulder/hamstring), CB Dontae Johnson (ankle), OLB Aaron Lynch (concussion), RT Erik Pears (knee), WR Torrey Smith (back/foot), LT Joe Staley (knee), SS Jaquiski Tartt (knee)
Questionable: CB Dwight Bentley (illness), LB Josh Bynes (foot), WR Calvin Johnson (ankle), DT Haloti Ngata (neck), T Michael Ola (knee), S Glover Quin (concussion), DT Caraun Reid (ankle), G Larry Warford (quadricep)