First chance?: Linebacker David Thornton missed practice with a shoulder injury suffered Sunday against Houston but could be back in action today, Fisher said.If Thornton is not able to play Sunday in Jacksonville, it appears Tennessee's top contingency plan is to move Peter Sirmon from middle linebacker to the left side and insert rookie Stephen Tulloch between Sirmon and Keith Bulluck."I'm comfortable, I'm ready, I've been ready since I got here," Tulloch said. "I had to learn a couple things since I got here but I am prepared for whatever happens. I'll play the best I know how to play."Linebacker Rob Reynolds, who rejoined the team after serving a one-week suspension, also could slide into Thornton's spot. But Tulloch said he's been told to prepare as if he'll start and said he's ready and raring to go."(Tulloch) has no choice," Bulluck said. "He's been around here for a whole camp, half a year, he's played in preseason games. Why not? It's about time to put him out there, see what he can do, let him run around. The vets on this defense are going to make sure he's all right."