Thomas was unable to practice all week after suffering the injury last week against Tampa Bay.
He will obviously be missed. Thomas has been a reliable and versatile back for the Saints all season with a team-high 549 rushing yards, a career-high 77 receptions for 513 yards and five combined touchdowns. He has also been an asset in pass protection.
The Saints are confident in their depth at tailback, though, especially with third-year pro Mark Ingram playing some of his best football over the past three weeks.
"We've kept five this year, which is unusual," coach Sean Payton said of the Saints' running back depth. "We felt those five guys were really important to what we do in our roster. Each one of those guys has a different skill set. The versatility is important."
The run game isn't a heavy part of the Saints' offense in a traditional sense. They ranked 26th in the NFL in rushing attempts and 25th in yards per game (92.1). However, they often employ their running backs in the pass game with a heavy dose of screen and swing passes. Sproles caught 71 passes for 604 yards this season.