Now, with misplaced infielder Felipe Lopez struggling mightily at third base and the Cardinals in the midst of a four-game losing streak, Mozeliak filtered through waiver wires and came out with Astros third baseman Pedro Feliz on Thursday.
"A lot has been written and said about us having to improve defensively at third base," Mozeliak said. "Defensively, [Feliz] ranks up there with almost any defensive third baseman in the game today."
To get the upgrade at the hot corner, Mozeliak gave up right-handed pitching prospect David Carpenter, a reliever for Class A Palm Beach. Carpenter, a converted catcher like current Redbirds reliever Jason Motte, has a 2.36 ERA this season in 49 appearances.
The question is now, will the Feliz upgrade on defense be offset by the subtraction from offense? Having his worst year as a pro at the plate, Feliz is hitting .221/.243/.311 for an OPS of .555 this season. He also has struggled somewhat in the field, with eight errors in 63 games at third base for a .942 fielding percentage.
Lopez has made 10 errors at third base this season for a .925 fielding percentage.
Mozeliak is confident that placed into a winning environment and the heat of a pennant race, Feliz offensive numbers will turn around. The right-handed hitter has a career .704 OPS, with a career .289 on-base percentage.
"Clearly, when you look at how he has performed historically over the last three or four years, he is traditionally in the .700 OPS," Mozeliak said. "If we can get that type of offense from him in the next six weeks, that would be a big positive from us."
The move will return Lopez to the super-utility role in which he enjoyed success earlier this season. Lopez was hitting .137/.241/.176 in 13 games this August.
"More importantly, it means [Lopez] can take a day off," Mozeliak said. "He has been playing through some things with his knees, and he is also trusted to play a position that is not his natural position. When you look at when this club was playing its best, we did have David Freese in the lineup and we had Felipe being able to play multiple positions, and this will allow us to do that."
In more unfortunate news, backup catcher Jason La Rue was placed on the 60-day disabled list on Thursday, ending his 2010 season. La Rue has been on the DL since receiving a concussion during the bench-clearing brawl with the Cardinals last week. La Rue was kicked in the head by Reds pitcher Johnny Cueto, who has since received a seven-game suspension.
According to Mozeliak, La Rue had shown no signs of recovery from the concussion, and the Cardinals deemed it safest to shut him down for the season.
"We have spoken with a lot of different medical experts on this," Mozeliak said. "It is obviously one that is not as clear-cut as you might have with an elbow or knee injury. There are a lot of unknowns.
"Given the way he is feeling and reacting, we really felt it was in his best interest not to have him feel like there is pressure to come back."
Michael Bleach is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.