SANTA CLARA -- It's all-hands-on-deck time for the 49ers when it comes to defensive linemen these days. Anyone and everyone is a candidate to play.
That's the result of starting defensive linemen Justin Smith (shoulder injury), Ray McDonald (biceps) and Glenn Dorsey (hamstring) being so banged up that they couldn't practice Wednesday. Smith and McDonald returned Thursday.
So it was that defensive coordinator Vic Fangio refused to rule out anyone for Sunday's game against the Tennessee Titans.
The 49ers already are without Ian Williams, who started the season as the nose tackle but now is on season-ending injured reserve.
Dorsey replaced Williams in the starting lineup. Now that he's hurting, second-year player Tony Jerod-Eddie is in line to make his first NFL start if Dorsey doesn't heal well enough between now and Sunday.
Practice squad player Mike Purcell is another candidate to join the defensive line rotation.
The fact Purcell participated in the team's offseason workouts and training camp makes him more experienced than fellow rookie defensive linemen Quinton Dial and Tank Carradine, Fangio said.
Fangio said Purcell is "ready to go if needed," as well as possessing the versatility to play nose tackle and defensive end.
Dial and Carradine practiced for the first time Tuesday. Therefore, their stamina is a concern if they are activated from the non-football-injury list and placed on the 53-man active roster.
Fangio said Dial looked good in practice Wednesday and that he might be a tad ahead of Carradine right now, if only because his injury wasn't as severe.
"They got to show it on the field," Fangio said of Dial and Carradine, "that they know what to do, rather than (just in) the meeting room. They're in the process of doing that."
This marked the first time Crabtree displayed how well he can run in front of the media since he suffered a torn Achilles during an offseason workout.
Earlier this month, coach Jim Harbaugh said Crabtree isn't expected back until mid-November, at the earliest, even though Crabtree is eligible to come off the physically unable to participate list at any time.
Crabtree also jumped forward several feet at a time as he launched a medicine ball toward a team athletic trainer.
Fangio said, "Patrick has covered some good tight ends in the past. Delanie is a very good tight end, as we all know, and we'll see how Pat does on Sunday."
Walker signed with the Titans during the offseason. He has caught 20 passes for 185 yards and two touchdowns the first six games this season.
He is on pace for career-highs in receptions, yards and touchdowns. He caught only 21 passes in 16 games last season.
Locker started the first four games before he suffered a sprained right medial collateral ligament and hip Sept. 29. Fitzpatrick has started the past two games.
On Thursday, Titans coach Mike Munchak cleared Locker for contact in practice, and Locker participated more than he did the day before, when he first returned from his injuries. Munchak also said he isn't ruling out Locker for Sunday's game. A decision is likely Friday.