LSU coach Les Miles confirmed following practice Wednesday that Perrilloux had been taking increased first-team snaps. On Friday, Miles said Flynn would be a game-time decision.
"Matt [Flynn] took part much more in practice on Thursday. [He'll] be a game-time decision," Miles said. "We'll get to the field, warm him up and see how it [shoulder] feels. If he's ready to play, we'll play him. If he's not, we won't."
Flynn, who battled through an ankle injury earlier in the season, injured his shoulder last Friday in the 50-48 triple-overtime loss to Arkansas.
If Flynn is unable to play or is limited, the Tigers will turn to Perrilloux for his first substantive action since early in the season. One of the nation's most sought-after prospects when he came out of high school, Perrilloux hasn't played at all in two of LSU's last four games. The 6-foot-2, 222-pound sophomore was suspended for the Alabama game and wasn't used against Arkansas. He did play briefly against Mississippi but didn't have a rushing attempt or attempt a pass.
Even so, Miles said Perrilloux has a much better command of the offense than he did earlier in the season.
"He's much more mature in football," Miles said. "Certainly, he's been through a season and understands what we're asking of him."
Tennessee's defensive staff was already preparing some for the possibility of seeing more of Perrilloux after hearing about Flynn's injury coming out of the Arkansas game.
"You don't know what they might do different with him, but you would think that the people they have been going to all year are the people they're going to continue going to," Tennessee defensive coordinator John Chavis said. "He's very talented and has a lot of good people around him.
"The other thing is that he and Flynn are very similar in what they do, so you don't have to change up a whole lot anyway in getting ready for them. We'll adjust our plan and be ready for both."
While Flynn may be iffy, the Tigers are getting a player back for this game.
Sophomore defensive end Ricky Jean-Francois, who's been suspended all season for academic reasons, has been reinstated, Miles said. Jean-Francois was a freshman All-American a year ago and one of the top defensive line prospects in the country when he came out of Carol City High School in Miami.
The Tigers, plagued by injuries in the defensive line, can use the depth.
"He'll take some snaps, I'll promise you," Miles said.
Chris Low is a college football writer for ESPN.com. Send your questions and comments to Chris at firstname.lastname@example.org.