The Oakland A's have traded Matt Holliday to the St. Louis Cardinals for Brett Wallace, Shane Peterson, and Clayton Mortensen.
All three guys are included in John Sickels top 20+ prospect list for the Cards coming into the season, with Peterson and Mortensen grading at C+, Wallace as an A-.
UPDATE -- John Sickels likes the trade for both teams. I think his analysis is probably about right, particularly if the Cards decided Wallace can't stick at third base.