KISSIMMEE, Fla. -- Astros pitcher Wandy Rodriguez left his start Friday against the Tigers after throwing just two pitches, suffering from a strained left oblique muscle. The left-hander is listed as day-to-day.

Rodriguez said he first felt a cramp on his left side while finishing his warmup session in the bullpen prior to taking the mound. He felt it again after throwing two pitches to leadoff hitter Ivan Rodriguez and immediately signaled to assistant athletic trainer Rex Jones. Within a minute, he was headed to the Astros' clubhouse.

Rodriguez said he had a similar injury in the Minor Leagues.

"It's not bad," Rodriguez said. "I'll be back soon. I won't be out too long."

Rodriguez is projected to be the club's second or third starter this season. Over three spring starts prior to his abbreviated outing Friday, Rodriguez had allowed five earned runs over 8 1/3 innings for a 5.40 ERA.

"Wandy should be OK," manager Cecil Cooper said. "It's just a little strain. He should be fine. He'll get some treatments tonight, see how it is [Saturday] and we'll go from there. We don't think it's anything serious."

The game with the Tigers continued after right-hander Chad Paronto replaced Rodriguez on the mound, but rain halted the game for good in the top of the second frame.