Locker was hurt late in the first half of a 29-27 loss to the previously winless Jacksonville Jaguars.
Locker ran an option play to running back Chris Johnson and was injured but stayed in the game. On the next play, he fumbled after failing to get a handoff to Johnson. He was replaced by Ryan Fitzpatrick on the following series.
"I really don't know how it happened," Locker said. "Just when I got up I could feel it."
Multiple reports said that the Titans believed Locker suffered a Lisfranc injury that could require surgery. BURKE: Cardinals in contention, props for Gus Bradley and more