METAIRIE - After watching six halfbacks go down with injuries in 2010, the last thing New Orleans Saints coach Sean Payton wanted to see was someone limping out of the backfield and into the locker room.

But it happened in the fourth quarter of Sunday night’s 62-7 win over the Indianapolis Colts when first-round draft pick Mark Ingram, the team’s leading rusher this season, bruised his right heel.

Ingram, who has 329 yards and three touchdowns on 85 carries, didn’t practice Wednesday, and Payton said he will be day-to-day for the rest of the week as they continue to prepare for Sunday’s game with the St. Louis Rams in the Edward Jones Dome.

If Ingram can’t play, Payton could have a capable replacement to add to a rotation that already includes Darren Sproles, who has 289 yards and two touchdowns, and Pierre Thomas, who has rushing 222 yards this season.

The Saints on Wednesday removed second-year running back Chris Ivory from the reserve/physically-unable-to-perform list. That started a 21-day window in which they must do one of three things: bring him up to the active roster, release him, or keep him on PUP the rest of the season.

Payton and other Saints officials likely won’t need the entire 21-day period to make up their minds, especially if Ingram continues to be slowed by his heel problem.

“With (Ingram), it’s day-to-day because really we’re just dealing with soreness and a bruise,” Payton said. “We’re dealing with that issue of just the pain and swelling and those types of things.”

Payton said the Saints training staff will see how Ingram is feeling Thursday morning and go from there as they closely monitor his progress.

If the problem lingers, Ivory, who led the Saints in rushing a year ago as an undrafted rookie with 716 yards and five touchdowns, is willing and able to help based on his first practice since suffering a Lisfranc fracture of his left foot in the regular-season finale.

“It felt real good man, it felt good,” Ivory, who also had surgery in August for a sports hernia, said of his first day back on the field. “I’ve been waiting for this for a long time. I felt like I did a lot of good things today. I still have to take it day-by-day and try to get used to the speed of the game.

“I have to focus on my aiming points and my reads and everything, but I think I did pretty good for the first day.”

If Ingram is sidelined for this week or longer, the Saints could activate the 6-foot, 222-pound Ivory and use him as they have Ingram this season - as their short-yardage and goal-line back.

Ivory excelled in that role last season despite battling injuries most of the season.

Payton said the first day back for Ivory was like the first day of training camp for the rest of the players in late July. In other words, he has to get used to playing with full pads in order to get acclimated to the game.

While the team doesn’t have to activate Ivory right away, Payton sounded like he will if Ingram is sidelined.

“The challenges beginning today are getting acclimated to the football specifics,” Payton said. “Not only did he take snaps with our offense, but he took a lot of scout-team snaps.

“The key is just getting into that football shape, where he’s used to contact and used to doing some of the things regardless of rehab and conditioning that you can’t simulate until you play football.”

But Ivory, who quickly became a fan favorite last season for his fearless attitude and bruising style of running, said nothing is holding him back, and he will be ready Sunday if he’s called upon.

“Yeah, most definitely, I could play,” he said. “But this whole week is going to play a big role in whether I get reps Sunday. Until then, I have to take it day-by-day and learn as much as I can before the game starts.”

Ivory said he didn’t feel real good until a couple of weeks ago when he was able to plant the foot and push off of it.

The next big thing, he said, will be getting used to full contact since teams seldom wear full pads and don’t tackle to the ground during in-season practices.

“I don’t think it’ll take much, just a couple of hits,” Ivory said. “Two or three hits and I’ll be good - just a little bit of contact and I’ll be all right.”

“We just have to be smart and make sure we’re getting him up to speed,” Payton said. “I know he’s in good shape.”