Alex Poythress, a five-star forward from Clarksville, Tenn., signed with Kentucky on Thursday. The 6-foot-8, 215-pound forward is rated the No. 18 overall prospect in the Class of 2012 by Rivals.com and No. 17 overall by ESPN.com. He also considered Vanderbilt, Memphis and Florida.

Poythress said he made his decision last Friday, according to Steve Jones of Rivals.com, and when he told Calipari, “he was screaming.”

Poythress is the third player in the Class of 2012 to commit to UK, along with five-star guard Archie Goodwin and four-star center Willie Cauley.

John Calipari said he isn’t commenting on recruiting until next week, when UK finalizes its class.