McAllister's release comes one day after the Jacksonville Jaguars cut the franchise's all-time leading running back, Fred Taylor. With a $7.5 million cap number and McAllister owed more than $5 million this fall, the Saints figured to either cut his salary or release him.
"I still have the itch to play," McAllister said, adding that he would not rule out returning to the Saints after he's been able to test the market.
"We've left that door ajar," Saints general manager Mickey Loomis said, but added, "I wouldn't call it likely."
His release puts the Saints under the $123 million salary cap.
McAllister had arthroscopic surgery on his left knee six weeks ago and said he could not pass a physical if he took one now. However, he expected to be ready by next season and believes he can play another three years or so.
McAllister said money was only part of the reason he wants to test the market. McAllister also said he wanted to see if a team out there would give him a greater role than he had last season in New Orleans, when he effectively worked as a third-string running back behind Reggie Bush and Pierre Thomas.
"If you're a player, you want [the ball] more," McAllister said.
In eight seasons in New Orleans, McAllister rushed for 6,096 yards on 1,429 carries.
Knee injuries have slowed him down the past couple of seasons. In his past two years, McAllister had only 131 carries and 510 yards.
Saints coach Sean Payton said the decision to release McAllister was one of the most difficult he's ever been part of as a coach. Payton said he marveled at McAllister's leadership ability, toughness, work ethic and his ability to connect with everyone from top NFL executives to fans.
"For the last four or five months, when I'm out going to eat or with my family, I can't tell you how many times a fan says, 'Hey, keep Deuce. Hang on to Deuce,'" Payton said. "So that's strong. It's a strong message and I think clearly, if you just pay attention, you appreciate and understand what this player has meant not really just on the football field but what he's meant in all other aspects."
John Clayton covers the NFL for ESPN.com. Information from The Associated Press was used in this report.