It might be more than you think. With Ulbrich out at least until the Sept. 15 game against Denver, and Rasheed listed as questionable for Thursday's season opener against the New York Giants, the Niners are considering keeping seven linebackers on their roster to begin the season.
In any case, they will definitely keep six and would like to sign one of the young prospects they let go to their practice squad. It's even feasible two linebackers will be signed to the practice squad.
Undrafted rookies Frank Strong and Brandon Moore, first-year player Cornelius Anthony and second-year veteran Quincy Stewart all have reached the final cutdown with formidable play in the preseason. Each has made plays at both linebacker and on special teams, and it's the latter factor that could be significant regarding who stays and who goes.
"They're being evaluated on two different areas," Niners coach Steve Mariucci said. "One being the linebacker spot, and also the other one that's equally important is the special teams contribution. And what happens is, sometimes a person can be a better linebacker than a special teams player or vice versa, so we have to take that into account."
And the sixth - or seventh - linebacker on this team probably won't be seeing much time on defense. So special teams play will weigh heavily.
So will potential, Mariucci said.
"None of them are going to be counted on as starters," Mariucci said. "So some of the evaluation has to be, ‘What will this guy be like in a month? What will he be like in a year?' Not always, ‘How good is he today?' Because they're not going to play much at linebacker today. So we have to take that into account, too."
Going strictly on training camp and preseason performance, Strong and Moore have the edge over the other two, although Moore's edge over Stewart is very slight. Strong and Moore were the team's leading tacklers against San Diego on Wednesday - Moore with six and Strong with five - and have been terrors throughout the season. Strong was the better of the two on special teams. He led the Niners in special teams tackles entering the San Diego game.
Anthony kept his hopes alive with outstanding play on special teams against San Diego, where he finished with three tackles to move ahead of Strong and lead the team during the preseason. At linebacker, Strong and Stewart tied for the team lead at that position with 14 tackles each.
It's hard to imagine the Niners not hanging onto Strong after the preseason he had. But they could say similar things about all four prospects who might ultimately be battling for one roster spot.