St. Louis Cardinals: Closer Jason Isringhausen will be sent on a rehab assignment after throwing to hitters Sunday for the third time in a six-day span.

Isringhausen will begin a brief rehab stint Thursday. He had been scheduled to begin the assignment Tuesday or Wednesday somewhere in the team's minor league system. But all of the teams are on the road until Thursday, when only Class AA Tennessee will be home.

Isringhausen will throw at Busch Stadium again Tuesday before leaving.

"I told them I'd go wherever they wanted me to go and this what they came up with,'' Isringhausen said. "Those two days aren't going to kill us. So, no big deal.''

There's a slight chance that the Cardinals might activate Isringhausen after Tuesday's session, skip the rehab assignment and use him in middle relief until he rounds into form.

"I'm there now and it's just a matter of going out there and facing hitters and getting into games,'' Isringhausen said. "I could do that and pitch in the sixth and seventh inning here.

"We haven't talked about everything yet, though.''

The Cardinals, who have blown 14 of 26 save opportunities without Isringhausen, won't commit to how long the rehab assignment will be. Isringhausen had 32 saves in 37 chances last year, helping the Cardinals win the NL Central.

"At this point, it depends on how he feels and how he responds, and also how sharp he is,'' general manager Walt Jocketty said. "It's too hard to predict.

"Hopefully it won't be long, but we really won't know until he starts pitching.''

The team was impressed with Isringhausen's pregame throw. He concentrated more on off-speed pitching than trying to blow away hitters So Taguchi and Wilson Delgado.

"He looked good,'' Jocketty said. "His curveball was better and he threw a nice changeup he's been working on, and his velocity seemed good.''

La Russa said it was important that Isringhausen, on the 15-day disabled list since March 21 following offseason shoulder surgery, be tested against hitters. Earlier in Isringhausen's comeback, he suggested the team might activate the closer without a rehab stint.

But on Sunday, he judged Isringhausen's outing for what it was worth.

"It's a workout against hitters on his own team and he's just trying to work on his delivery, work on his pitches,'' La Russa said. "It's not the same kind of intensity.

"I think when he gets out there against other people it'll be a better read.''

This is Isringhausen's third attempt at getting ready for the season after stiffness stopped him in two other efforts.

Arizona Diamondbacks: Arizona Diamondbacks center fielder David Dellucci suffered a concussion and remained motionless for more than four minutes after he collided with shortstop Alex Cintron chasing a fly ball Sunday.

Dellucci was down in a prone position on his stomach, then finally sat up with some help. About one minute later, Dellucci was helped to his feet.

A grounds crew cart then came onto the field and took Dellucci to the Diamondbacks dugout.

San Diego's Miguel Ojeda lifted a shallow fly to lead off the third inning. As Cintron reached out for the ball, Dellucci went into a slide and tried to avoid contact.

But just as Cintron made the catch, his left knee appeared to hit Dellucci in the face. Cintron held onto the ball as he flipped over Dellucci.

Despite being shaken up, Cintron remained in the game. Steve Finley replaced Dellucci.

Colorado Rockies: Ronnie Belliard left the Colorado Rockies' game against San Francisco in the sixth inning after hurting his right ankle while running the bases.

After reaching first with a single, Belliard ran hard toward second as the Giants turned a double play on Jay Payton's grounder.

Belliard attempted to stop before he reached the base -- in doing so, he awkwardly planted his right foot, then stumbled forward three steps before flopping on the dirt.

Belliard rolled onto his back and held his ankle as manager Clint Hurdle and the Colorado trainer rushed to him. He was helped off the field a few minutes later.

Brent Butler replaced Belliard at second base in the bottom of the inning, making a diving stop of Marquis Grissom's grounder a few moments later.

Belliard was 2-for-3 when he left. He has started 46 of the Rockies' 57 games at second base, and he's hitting .452 (14-for-31) over Colorado's last eight games.