Saints head coach Sean Payton revealed after practice Friday that second-year RB Chris Ivory has undergone sports hernia surgery.

Ivory, a rookie free agent last season who gained 716 yards on 137 carries (5.2 avg.) with five touchdowns, had missed all of training camp as he recovered from offseason foot surgery.

Payton said that Ivory underwent the surgery in Philadelphia and is expected to have a three-week recovery period.

This news comes a day after the Saints released backup RB Lynell Hamilton, a decision Payton called one of the toughest of his career.

"He's kind of what we point to as the type of player we're looking for," Payton said. "It was becoming more difficult for him with the depth we have at running back. That was a hard decision, but it was one we made."

Hamilton is coming off a torn ACL injury suffered in 2010 preseason that knocked him out for all of last season.

Payton said he expects Hamilton to sign with another team but added that if Hamilton does not get another shot, he would like to re-sign Hamilton in midseason.

The team's RB depth chart currently includes Pierre Thomas, Mark Ingram and Darren Sproles.