PORT CHARLOTTE, Fla. — Tampa Bay reliever Jason Isringhausen will begin the season on the disabled list, a move that will give him additional time to build arm strength following elbow surgery and potentially bolster depth in the Rays' bullpen.

The defending AL champions purchased the 36-year-old right-hander's contract from Triple-A Durham and plan to put him on the 15-day DL Sunday, the day before the Rays open the regular season in Boston.

"It was something that was important to both sides," said Rays executive vice president of baseball operations Andrew Friedman.

"We feel like there is a very good chance that at some point in 2009, Jason will help us win games," Friedman said. "We're going to be fairly methodical here in terms of getting him all the way back. We've seen a lot of good things this spring. And by doing this, we feel like it greatly increases the chances of him helping in a meaningful way."

Isringhausen, who was added to the 40-man roster on Wednesday, wasn't interested in beginning the season in the minor leagues. He could have asked to be released, but both sides were committed to finding a way he could stay.

"There were a lot of options we could have gone through," the right-hander said. "But I think we came up with the best one to suit everybody's needs. That was the bottom line."

A veteran of 13 major league seasons, Isringhausen spent the last seven years with the St. Louis Cardinals. Injuries limited him to 42 appearances and 12 saves in 2008, his lowest total since converting to closer in 1999.

He served two stints on the DL last season and has not pitched in a regular season game since mid-August because of right elbow tendinitis and a partial tear of his flexor tendon. He had surgery in September, and the Rays signed him to a minor league contract on Feb. 20.

The right-hander appeared in six exhibitions this spring, allowing four runs and eight hits in six innings. He walked one and struck out five.

"I feel healthy. But in the same sense, I know I can get sharper. And to pitch in the American League East, you need to be as sharp as you can be," Isringhausen said. "I don't want to go out there half-stepping."

While Friedman said there's no timetable for Isringhausen to be ready to join the bullpen, the right-hander expects it to be a few weeks.

"It won't be a couple of months," the reliever said. "I wouldn't think so unless there is some kind of setback."

Isringhausen's 293 career saves are the sixth highest among active players.

"This guy is obviously very talented, has a lot of experience pitching late in games and provides even more depth for us," Friedman said. "We feel like it's a very good thing for us and ... a good thing for him as well."