The comeback attempts of 49ers linebacker NaVorro Bowman and nose tackle Glenn Dorsey officially ended for the season on Saturday.
The 49ers on Saturday placed Bowman and Dorsey on season-ending injured reserve to create roster space for cornerback Marcus Cromartie and guard Andrew Tiller to be promoted to the 53-man roster so they can be available to play Sunday against the Seattle Seahawks.
The 49ers are low on cornerbacks with Tramaine Brock (hamstring) ruled out and Chris Culliver (knee) questionable for Sunday's game. Perrish Cox, Dontae Johnson and Leon McFadden are the only other healthy cornerbacks.
Cromartie (6 foot, 195 pounds) was signed to the 49ers practice squad this season after being waived by the Cleveland Browns. He originally signed with San Diego last year as an undrafted rookie from Wisconsin. Cromartie will wear No. 47.
Tiller is needed with rookie center Marcus Martin (knee) questionable for Sunday's game. Tackle Anthony Davis (concussion) has been ruled out. If Marcus Martin is unavailable, Joe Looney would start at center and Dillon Farrell would be the 49ers' only backup offensive lineman. Tiller will wear No. 61.
The roster moves ends the seasons for Bowman and Dorsey.
The 49ers activated Bowman off the physically-unable-to-perform list on Tuesday in hopes that he could practice at some point this season. He has been rehabilitating his surgically repaired left knee after he sustained a devastating injury against the Seahawks in the NFC Championship game.
Dorsey sustained a torn left biceps tendon early in training camp. He was originally placed on injured reserve/designated for return. But after returning to the 53-man roster on Nov. 17, Dorsey was unable to return to full strength.
The 49ers now have 17 players on season-ending injury lists, including 13 on injured reserve:
LB NaVorro Bowman (knee)
LB Patrick Willis (toe)
NT Glenn Dorsey (biceps)
NT Ian Williams (leg)
C Daniel Kilgore (leg)
TE Vance McDonald (back)
TE Derek Carrier (foot)
DB Jimmie Ward (foot)
CB Chris Cook (groin)
RB Kendall Hunter (knee)
CB Kenneth Acker (foot)
WR Chuck Jacobs (knee)
G Fouimalo Fonoti (knee)
Reserve/Physically unable to perform
DT Kaleb Ramsey (Achilles)
FB Trey Millard (knee)
CB Keith Reaser (knee)
G Brandon Thomas (knee)