METAIRIE, La. -- Another player who contributed to the New Orleans Saints' Super Bowl run has to be replaced for a few games.
Tracy Porter will be out three to four weeks after arthroscopic surgery to repair the lateral meniscus in his left knee, leaving a team that has already looked vulnerable without one of its starting cornerbacks.
Four regulars were unable to practice Wednesday: Porter, defensive end Will Smith (groin), and running backs Reggie Bush (right fibula) and Pierre Thomas (left ankle). Then there were players -- including strong safeties Roman Harper (hamstring) and Pierson Prioleau (chest) -- who were banged up but practiced on a limited basis with the hope of being able to play at Arizona on Sunday.
"Part of the success that you have in this league has a lot to do with how you respond to injuries and how a team can persevere through some of the unfortunate things that happen," said Prioleau, a special teams captain who started at safety last Sunday in place of Harper but was knocked out of the game on kick coverage.
"It's obvious that we've had to endure some injuries to some key players in key spots on this team, but it's going to show the mark of the team that we are to have the ability to come out and still produce on the field with the guy that's next in line."
In all, 19 players were listed on New Orleans' injury report, although 12 practiced fully.
The Saints (3-1) have found a way to win and are tied for first place in the NFC South. But their performances haven't approached the level of dominance they displayed last season, when they won each of their first six games by double digits.
After opening the season with a five-point win over Minnesota, the Saints edged winless San Francisco with a last second field goal, lost to the Falcons in overtime after missing a field goal that could have won it, and then needed a field goal late in the fourth quarter for a two-point, comeback victory over winless Carolina.
The Saints contend their best football is still ahead, given how many players are out or playing hurt.
Rookie running back Chris Ivory, who had 12 carries against Carolina, favored his left knee with a pronounced limp as he made his way from the trainer's room to his locker.
Ivory's path to the regular season roster was cleared in training camp by season-ending injuries to Lynell Hamilton and P.J. Hill. Then when Bush went out after Week 2, Ivory began to see significant action the past two games and the Saints signed Ladell Betts, who is now the only running back not listed on the injury report.
Brees said the club's running back situation exemplifies how the Saints have been forced to overcome factors beyond their control as they try to defend their title.
"Did I think at this point that Ladell Betts and Chris Ivory would be our two starting running backs going back to training camp? I don't think they were on the radar at that point," Brees said. "Anytime some of your key components are not on the field, it's going to affect you a little bit and you just kind of wait for the time to put all the pieces to the puzzle back on the field. I feel that the guys that have stepped in have done a very good job."
Saints coach Sean Payton said the Saints worked out two safeties this week -- Macho Harris and Pat Watkins -- but decided against signing either because the club hopes either Harper or Prioleau can play Sunday. When both were out on Sunday, Chris Reis went in at strong safety, only to leave the game with a season-ending shoulder injury. Then Usama Young, already a regular on special teams, had to fill in at strong safety.
Young was drafted as a cornerback and is now a reserve free safety, so moving to strong safety on Sunday required him to contribute on run support more than he is accustomed.
"You've got to be able to have that linebacker's mentality," Young said. "You've got to be able to close some gaps and it happens fast."
After Young tackled DeAngelo Williams for a loss late in the fourth quarter -- a crowd-pleasing play which took Carolina out of range for a winning field goal try -- Young said he briefly thought to himself that he could get used to playing strong safety.
"But when I went home that night I started feeling my neck getting a little tight, the shoulders were hurting and I said, 'Man, being in (on run support) takes it out of you," Young said.