Kolten Wong's every-day job at risk when Jhonny Peralta comes off DL

ST. LOUIS -- The Cardinals locked up second baseman Kolten Wong to a five-year, $25.5 million contract extension in spring training, but his grasp on an every-day job is far from secure.

On Friday, general manager John Mozeliak unveiled the team's plans when Jhonny Peralta returns from the 15-day disabled list, most likely on Tuesday. Hot-hitting rookie Aledmys Diaz will remain at shortstop, Peralta will shift to third, and Matt Carpenter will get the bulk of his playing time at second base.

Wong could be left without a position many days, which could make him a trade chip or a candidate to be optioned to Triple-A.

"Obviously, at-bats are going to be harder and harder to come by," Mozeliak said. "Clearly, it comes down to performance. At any point, if he were to take off and get moving, he would find playing time. It's always about finding that piece that, from a trajectory standpoint, is going up. Right now, I think that's the only position we're sort of struggling with."

Wong, 25, is batting .225 with a .603 OPS and five errors this season.

What made Peralta's return something of a puzzle for the Cardinals is the emergence of Diaz, who went into Friday batting .328. Mozeliak said St. Louis didn't want to ask Diaz to move positions despite his league-high 12 errors because the organization thinks he could be the "shortstop of the future." Diaz's defense has improved; he rates higher in advanced metrics than he does in statistics like fielding percentage, and he has better range than Peralta.

Mozeliak said he spoke with Peralta about moving positions. Peralta is at the team's Florida spring training facility getting at-bats after a rehab assignment in Class A Peoria and Double-A Springfield in which he batted .200 in 16 combined plate appearances.

"Obviously, if we felt like it was something he wouldn't do, we wouldn't be talking about it publicly," Mozeliak said. "We'd have addressed it internally."

Mozeliak said he and manager Mike Matheny spoke with Carpenter about returning to the right side of the infield and that he welcomed the change. Carpenter played second base in 2013 and plays occasionally at first base.