ARLINGTON -- Rangers right-hander Jason Jennings was back with the club on Thursday, but it will be some time before he returns to a mound.

Jennings underwent season-ending surgery on May 30 to repair a torn flexor tendon in his right elbow. He had the same procedure performed Aug. 30, 2007, while with the Astros. Following that procedure, MRIs indicated Jennings would make a full recovery.

However, with the first surgery having taken place toward the end of the 2007 season, Jennings pushed himself to return to action this season. In retrospect, he might have pushed himself too hard.

"I followed my plan and I was throwing the ball well," said Jennings with his right arm tucked into a sling. "I didn't think much of it when I started feeling discomfort. Looking back, maybe I did rush it."

This time around, Jennings is going to be more cautious. Having spent significant time on the disabled list since fracturing the middle finger on his throwing hand midway through the 2005 season, Jennings knows he's running out of chances.

Jennings said he's already doing range of motion exercises and he thinks he'll be able to start throwing in September. However, with more time to recover from this most recent surgery, he said his rehab process would be conservative.

"I think what he learned and what we learned is to take it slow," manager Ron Washington said.

In six starts this season, Jennings was 0-5 with an 8.56 ERA and 18 walks compared to just 12 strikeouts. He's been on the DL since April 30, the day after he exited a start against the Royals in the third inning.

"Little did I know it'd been torn all along," Jennings said. "It was actually a relief to find out something was wrong."

In 2006, Jennings was 9-13 with a 3.78 ERA with the Rockies and had 142 strikeouts to 85 walks in 212 innings. In 2002, his first full season in the Major Leagues, Jennings went 16-8 with a 4.52 ERA for Colorado.

The Rangers signed Jennings on Jan. 17 to a one-year deal hoping that, with a fully healthy arm, he could translate that kind of success at Coors Field to similar success at Rangers Ballpark in Arlington.

Although Jennings never looked like his former self this season, lacking the velocity and sink he used to get on his fastball, Washington said the team never imagined Jennings would suffer the same arm injury that surgery was supposed to have corrected a year ago.

"We expected that the more we gave him the ball, the stronger he would get," Washington said. "Nobody expected what happened to happen."