A Major League source has confirmed that a deal is in place for the Cardinals to acquire Matt Holliday from the A’s in exchange for Brett Wallace, Triple-A right-hander Clayton Mortensen and Double-A outfielder Shane Peterson. ESPN reports that Oakland will send some cash to St. Louis to help offset some of the remaining cost of Holliday’s contract.

Holliday has long been a target of the Cardinals, who talked trade with Colorado over the winter before the Rockies shipped the three-time All-Star to Oakland. He bolsters the team’s outfield and offers the cleanup hitter that manager Tony La Russa has long coveted to slot behind Albert Pujols in the Cardinals lineup.

Holliday, 29, can be a free agent at the end of the 2009 season. His current contract pays him $13.5 million, of which approximately $6 million is still due.

Wallace, 22, was St. Louis’ first-round pick in the 2008 Draft and has rocketed through the Minor Leagues. He is currently playing at Triple-A Memphis. Mortensen, 24, is also at Memphis and was a supplementary first-rounder in 2007. Peterson, 21, was a second-round selection in 2008.

–Matthew Leach