Braden Looper will pitch on Tuesday at home against Houston, followed by Adam Wainwright, Kyle Lohse and Todd Wellemeyer. Pineiro will return to the rotation on May 31 at home against Pittsburgh. Monday's off-day is the second in five days for St. Louis.
"Pineiro's groin is barking a little bit," La Russa said. "So I think we're going to take advantage of that. We're going to hold Pineiro till a spot opens, which will be over the weekend."
Looper will still receive an extra day of rest, since his previous start came before the club's Thursday off-day. The remaining three pitchers will each be pitching on a normal five days' rest.
For Looper, it's been an encouraging year despite some so-so games recently. In fact, it's been an encouraging year in part because of those so-so games. With one exception, Looper has avoided the disastrous games that he encountered on several occasions last year, his first year as a big league starter. When he's been less than sharp, he's kept the game within reach.
"I really feel like I'm getting close to being where I want to be," he said. "Not that I was hurt before, but I think you go through a period where you just don't feel as good. When you're out there doing it, you don't have pain. I don't know how to explain it, but going through it, you don't feel crisp or sharp. I felt like last game I was getting close. So hopefully that's a sign."
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.