"I spoke with him yesterday and he's pretty confident that he'll be ready to go," Mozeliak said. "In this case we've been able to be a little more patient, so I think from a strength standpoint he's about where he needs to be."
The Cardinals plan to play Peralta at third base to keep Aledmys Diaz at shortstop. The move would shift Matt Carpenter to the right side of the infield, where he played predominantly in 2013, and leaves Kolten Wong with an uncertain future. Wong entered Friday hitting .225/.312/.292 this season in 138 plate appearances.
"Obviously at-bats are going to become harder and harder, so clearly it comes down to performance," Mozeliak said. "At any point, if [Wong] were to take off and get moving, he would find playing time."
Peralta has 213 games of experience at third base, but he hasn't played the position since 2010 with Detroit. He's played 300 games at shortstop for the Cards over the past two seasons, and he was slated to start there this season before landing on the disabled list in March.
Peralta's injury cleared a spot for Diaz, who got off to a torrid start and entered Friday still pacing St. Louis with a .328 batting average, but Mozeliak stated that Peralta returning also means the Cardinals can afford to give Diaz a few more days off.
"I think the key thing for him would be just to have his bat somewhere in our lineup," Mozeliak said. "I think when you look at our infield flexibility, Carpenter is willing to play on the right side if need be, and we do want to keep developing Diaz at short, so we're going to be patient there."
Peralta suffered a minor setback in his rehab this week due to a cut finger, but he is scheduled to resume playing at Class A Advanced Palm Beach this weekend. He's 3-for-15 in six rehab games across two Minor League levels.
Joe Trezza is a reporter for MLB.com based in New York. Follow him on Twitter at @joetrezz. Nick Krueger, an MLB.com reporter based in St. Louis, contributed to this report.