Both the inside linebacker and nose tackle were placed on season-ending injured reserve Saturday thwarting their comebacks from injury. Bowman was added to the 53-man roster this week after tearing his ACL and MCL in his left knee in last January's conference title game.
Dorsey had been in and out of practice over the last few weeks since being activated from injured reserve with the return designation Nov. 17. He sustained a torn biceps tendon tear in his left arm early in training camp.
Bowman had been rehabbing vigorously since sustaining the injury. Head coach Jim Harbaugh went as far to say his All-Pro inside linebacker had a shot of returning this season, perhaps coming back to the field in Week 16, 17, or if the 49ers miraculously found a way to the playoffs.
A candid Bowman spoke to the media this week, saying his plan was to return in 2014 all along and not shut things down early to prepare for next season.
"I’ve just worked. Dealt with the injury, accepted it, looked at other guys overcoming their injury and always saying to myself ‘If that person can do it, I can do it.’ That’s what really drove me," Bowman said.
"I never said I was going to throw in the towel and not come back and play. I’ve always just worked. If it felt good, it felt good. If it didn’t, hopefully people understand."
Without Bowman and Dorsey, San Francisco's defense has remained strong, ranked third in the league heading into Sunday's game against the Seattle Seahawks.
Cromartie, who will wear No. 47, has been tapped because of the uncertain playing status for corners Chris Culliver (knee) and Tramaine Brock (hamstring). Both were limited participants in practice this week and are questionable for Sunday.
Brock has not appeared in a game since Nov. 9's win against the New Orleans Saints. He's only played in three games all season while previously dealing with a toe injury suffered in the season opening win over the Cowboys.
Tiller was added to provide insurance to the offensive line if rookie center Marcus Martin is unable to play Sunday after injuring a knee in last week's loss to the Raiders. He is listed as questionable.
If Martin can't play, it's likely Joe Looney takes over center with Dillon Farrell as his backup. Tiller will wear No. 61.