Kyle McClellan, who is 6-2 with a 3.86 ERA in his first year in the rotation, strained a hip flexor muscle in the first inning Monday against San Francisco when he landed awkwardly. The right-hander allowed seven runs in four innings.
"You think maybe it's just a one-time thing," the 24-year-old McClellan said. "By the time I realized it wasn't I was already in some hot water."
The Cardinals recalled right-hander Lance Lynn from Triple-A Memphis to start Thursday against the Giants, giving the rest of the rotation an extra day of rest.
Holliday returned from a six-game absence with a left quadriceps injury Monday but was a lineup scratch on Tuesday, striking out as a pinch hitter. He's batting .342, four points ahead of teammate Lance Berkman for the league lead, with six homers and 31 RBIs.
"Frankly it looks like it's getting better, but it's still something he feels," general manager John Mozeliak said. "It's just not going away."
Manager Tony La Russa said Holliday appeared to respond well to hard workouts last weekend and told the team he was ready. But Holliday had a lot of trouble running Monday, and perhaps cost the team a run when he shuffled to first on a grounder he otherwise could have easily beat out after third baseman Miguel Batista bobbled the ball.
Holliday remained on the roster Wednesday night against the Giants, partly because St. Louis couldn't get a replacement player in time.
"He felt something where he was hoping not to feel anything," La Russa said.
Mozeliak said the team already had been a little concerned with McClellan's load. He has worked 67 2/3 innings, close to his season total the previous three years when he was a setup man. Last year, McClellan totaled 75 1-3 innings in 68 appearances.
"At some point we were going to have to probably slow him down anyway, and this is just a nice opportunity to do that," Mozeliak said. "Let him get to 100 percent and lower his inning count."
Twice last month, McClellan worked eight innings. He said there's been no fatigue.
"It says a lot about them to put my health first," McClellan said. "If you look at the innings in the past and the pace I'm on, it makes sense to take this time and back off and really make sure this is healed, and kind of give everything a chance to reload."
The 24-year-old Lynn was a supplemental first-round pick in 2008 out of Mississippi and will make his major league debut. He's 5-3 with a 4.06 ERA in 10 starts at Memphis and was a 13-game winner there last season.
Berkman has batted cleanup during Holliday's absences and will continue in that role, and La Russa said Allen Craig and Jon Jay will get more playing time in the outfield. Jay was batting .349 with four homers and 14 RBIs and Craig was batting .337 with three homers and 19 RBIs.