Saints head coach Sean Payton confirmed that RB Mark Ingram and LB Will Herring have been placed on injured reserve.
Ingram, a first-round pick, will have surgery to repair turf toe. Herring suffered a sprained MCL.
In 10 games and four starts, Ingram led the Saints with 122 carries and was third with 474 rushing yards. He tied Pierre Thomas for the team lead with five rushing touchdowns.
Herring had five tackles and an interception on defense and four special-teams tackles.
To replace Ingram and Herring on the roster, the Saints signed OL Eric Olsen off the Redskins' practice squad and promoted LB Nate Bussey.
The Saints host the Lions in the wild-card round of the playoffs on Saturday night.