Isringhausen started the ninth inning against the Nationals on Saturday night. After Elijah Dukes greeted him with a single, the veteran right-hander retired Willie Harris on a flyout and struck out Austin Kearns swinging before facing Corey Patterson. That's when Isringhausen threw a wild pitch and looked to the dugout, alerting Rays manager Joe Maddon that something was wrong.
Isringhausen had to leave the game, and Lance Cormier came on to get the final out in the Rays' 8-3 win.
For now, the Rays are calling the injury a strained elbow.
"MRI tomorrow, it's an elbow strain, we'll know more at that particular juncture," Maddon said. "We won't really know until we get the MRI. I just know yesterday he didn't feel real good."
Isringhausen had season-ending elbow surgery with the Cardinals last season before signing with the Rays at the beginning of Spring Training. He began the season on the disabled list before he joined the team on May 18. He is 0-1 with a 2.25 ERA in nine games with the Rays this season.
Isringhausen has compiled 293 career saves, sixth highest among active players and 22nd on the all-time list. Since 2000, his 284 saves rank tied for third (with Billy Wagner) among Major League pitchers, trailing only Mariano Rivera and Trevor Hoffman. He is also the all-time Cardinals leader with 217 saves.
Isringhausen was selected to the National League All-Star Team in 2005 and the American League squad in 2000. He has pitched in five postseasons with St. Louis and Oakland and reached the World Series in 2004. In 23 career postseason appearances, he is 1-1 with 11 saves and a 2.36 ERA; he saved a career-high 47 games in 2004, tied for the National League lead.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.