A right elbow strain that has bothered Lopez for two weeks finally landed him on the 15-day disabled list on Monday. The Cardinals recalled infielder Tyler Greene from Triple-A Memphis to take his place, and St. Louis also sent outfielder Allen Craig to Memphis and recalled outfielder Jon Jay.
Lopez, 29, has been dealing with discomfort in his throwing elbow since the Cardinals' April 11 game in Milwaukee. However, he didn't notify the club of any problem until after he started on April 19, two days after he pitched in the 20-inning St. Louis loss to the Mets. Lopez explained that what he first felt was not pain, and the condition worsened in the days after he pitched.
"It was just tightness," Lopez said. "It wasn't what it is now."
Lopez did not point to his experience pitching as the cause for the injury, and manager Tony La Russa likewise downplayed such a direct parallel. The correlation, though, can't be dismissed entirely. Lopez first felt something when he slid headfirst into second base in that April 11 game.
"It's a couple of things," Lopez said. "Pitching obviously didn't help the situation, but at the time, I thought I could do it."
Still, Lopez said that he didn't hesitate to accept the assignment when he was asked to pitch.
"I never say no to whatever," he said. "If the team needs me and I have only one leg, I'll do it. It's whatever I can do to help the team."
Lopez appeared in all three games of the Cardinals' just-ended weekend series in San Francisco, so the move cannot be backdated. He is hitting .273 with a .347 on-base percentage and a .432 slugging percentage, and he has started three games apiece at second base, shortstop and third base.
His spot will be taken by Greene, 26, who was hitting .275 with a .351 OBP and a slugging .435 at Memphis. Greene is a gifted defender but struggled this spring, likely costing himself a chance to make the Opening Day roster.
"We know he's a better player than that," manager Tony La Russa said.
Jay, 25, will be on the Major League roster for the first time in his career. He was batting .347 at Memphis with a .420 on-base percentage, a .542 slugging percentage, seven stolen bases in seven chances and 16 runs scored in 17 games. The lefty hitter replaces the right-handed-hitting Craig, 25, who went 1-for-18 in his first taste of the Majors.
Things added up well for Jay. Lopez's DL stint means that the Cardinals will have no other left-handed batters on the bench as of Tuesday, when Jason LaRue will be activated from the DL and Bryan Anderson sent down. Moreover, Craig wasn't benefiting from irregular playing time, in the club's view.
"It's a good switch for us," La Russa said. "Gives us a little left-handed balance we didn't have there before, and it gets Craig playing. So it's like win-win. Even if Felipe had been here, there's a good chance we would have made the move, just to get Craig playing."
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.