TEMPE, Ariz. - NFL career rushing leader Emmitt Smith has a broken left shoulder blade and will be sidelined indefinitely.

The injury occurred early in the second quarter of Arizona's 24-7 loss to Dallas on Sunday in Smith's first game against the team he spent his first 13 seasons with and led to three Super Bowl victories.

Coach Dave McGinnis said X-rays taken Monday revealed the injury was more serious than originally thought. After the game, the Cardinals said Smith had only a sprained shoulder.

Team orthopedist Russell Chick found the break to the scapula in the back of Smith's shoulder after a more thorough examination.

''If it was just a bruised shoulder, believe me, Emmitt Smith would have come back out of that locker room,'' McGinnis said.

Smith was unavailable Monday, leaving without speaking to reporters.

McGinnis acknowledged Smith would be out for at least a few weeks, but doubted his season was over.

''I'm not going to put a time frame on it because I've not been given a time frame on it,'' McGinnis said.

On his final play, Smith went between the guard and tackle on the left side. Safety Roy Williams arrived in the hole when Smith did and tackled the former Cowboy, causing the injury.

The injury is sure to sideline Smith longer than anything in his experience: He's missed just four games because of an injury.

Smith lost 1 yard on six carries and caught two passes for 2 yards against the Cowboys, spoiling his debut against his former team. The eight-time Pro Bowler broke Walter Payton's career rushing record last season, and has 17,354 in his career.

He had just 192 yards and one touchdown in five games with the Cardinals.

During warmups Sunday, Cowboys fans cheered Smith and held signs welcoming him back to Dallas. Smith wept during postgame interviews, a sign of his disappointment at being held without positive yardage for the first time.

''I know he handled it with extreme professionalism, handled the whole situation with extreme grace,'' McGinnis said.

Marcel Shipp, who led the Cardinals in rushing with 834 yards last season and was tabbed as the starter until Smith signed with the Cardinals in March, will start at running back.

His backups are Damien Anderson and special teams star Josh Scobey, who had a 100-yard kickoff return against St. Louis on Sept. 28 and a 63-yard kickoff return Sunday.

''Hopefully our running game will work - we can make it work - enough so that I have to run all three of them,'' McGinnis said. ''But so far, we've had trouble getting enough carries to one guy.''