NEW ORLEANS (Reuters) - The New Orleans Saints will enter the playoffs without their top two running backs after announcing on Wednesday that Pierre Thomas was placed on injured reserve with an ankle injury.

Thomas helped the Saints capture the Super Bowl a year ago but was limited to six games this season because of ankle problems. Leading New Orleans rusher Chris Ivory was placed on the IR a day earlier because of a foot injury.

The Saints (11-5) open the postseason against the Seattle Seahawks on Saturday and will have to lean heavily on Reggie Bush.

A threat as a runner and pass catcher, Bush missed eight games this season with a right leg fracture and has rushed for just 150 yards.

New Orleans has filled Thomas' spot on the roster by signing running back Joique Bell, the Saints said on their team website (http://www.neworleanssaints.com). (Writing by Jahmal Corner in Los Angeles; Editing by Peter Rutheford)