Two 49ers starting offensive linemen missed Wednesday’s practice: right guard Alex Boone, who is dealing with a knee injury, and center Marcus Martin, who was out with an undisclosed illness.
Boone was injured on the play in the third quarter Saturday during which quarterback Colin Kaepernick fumbled and the Chargers recovered the ball in the end zone. Joe Looney had been the team’s top backup at guard. However, he appeared to be demoted Saturday -- he was inactive -- after what offensive coordinator Greg Roman said was a “tough game” at center the previous week.
Jonathan Martin, Dillon Farrell and Andrew Tiller are the other backups along the offensive line. Boone has not missed a start due to injury since he became the starting right guard in 2012.
Meanwhile, cornerback Perrish Cox has missed the first two practices of the week with a shoulder injury. If he can’t play, rookie Dontae Johnson likely would start, although Tramaine Brock (hamstring) has gone through some limited practices this week.
Did not participate: G Alex Boone (knee), CB Perrish Cox (shoulder), RB Carlos Hyde (ankle), WR Stevie Johnson (knee), C Marcus Martin (illness), S Eric Reid (concussion), DE Justin Smith (back), S Ray Ventrone (groin)
Limited: CB Tramaine Brock (hamstring), LB Ahmad Brooks (thumb), CB Chris Culliver (knee), WR Bruce Ellington (hamstring)
Full: WR Michael Crabtree (knee), WR Brandon Lloyd (knee)
Did not participate: S Deone Buccanon (knee), TE John Carlson (calf), LB Larry Foote (knee), QB Drew Stanton (knee).
Limited: LB Lorenzo Alexander (knee), WR Jaron Brown (foot), DE Calais Campbell (hip), G Jonathan Cooper (wrist), S Rashad Johnson (ankle), G Ted Larsen (shoulder), LB Matt Shaughnessy (shoulder)
Full: WR Larry Fitzgerald (knee), S Tyrann Mathieu (thumb)
Read Matt Barrows’ blogs and archives at www.sacbee.com/sf49ers.