The Saints didn't elaborate on the severity of the injury, but Thomas' status may be in doubt for Saturday night's playoff opener at Philadelphia.
Thomas, who suffered the injury during Sunday's 42-17 victory over the Tampa Bay Buccaneers, would be a big loss for the Saints.
He ran for a team-high 549 yards this season and caught a career-high 77 passes for 513 yards, scoring a combined five touchdowns. The Chicago native also has a history of coming up big for the Saints in cold-weather games.
The good news for New Orleans is that if Thomas is out or limited, the Saints have a deep backfield at their disposal. Versatile running back Darren Sproles can easily pick up the slack in the passing-game personnel groups. And backups Mark Ingram and Khiry Robinson have been impressive in limited roles lately.
Ingram has been playing some of the best football of his three-year career in the past three games, with 108 yards on 17 carries (6.4 yards per carry) and four receptions for 49 yards.
"I prepare myself every week like I'm gonna take all the reps. So if he can go, of course we want him to go. But if he can't, we'll step up. We have guys who are excited and ready to play," said Ingram, a former Heisman Trophy winner and first-round draft pick, who has stayed patient and positive throughout three seasons plagued by injury and inconsistent production.
"That would be awesome, to play the best game of my career -- the best game of my life -- in that first playoff game. And hopefully just continue to get better. So I'm excited about it and looking forward to it."
The rest of the Saints' injury report is in good shape. Backup safety Rafael Bush (ankle) practiced Thursday on a limited basis after being held out on Wednesday. Everyone else has fully participated all week.