Seattle Mariners pitching prospect Taijuan Walker will make his major league debut on Friday when he starts against the Houston Astros.
Walker, who turned 21 two weeks ago, has not been officially added to the 25- man roster. The Mariners will need to make a corresponding roster move.
The 6-foot-4 right-hander was the Mariners' first pick in the 2010 MLB Draft, as a supplemental first-round selection (43rd overall). He is considered as one of the top prospects in baseball, having played in the past two All-Star Futures Games and is listed on MLB.com as the No. 1 Mariners prospect and No. 4 overall prospect.
Walker has started 25 games for Double-A Jackson and Triple-A Tacoma this season, posting a 9-10 record with a 2.93 ERA and 160 strikeouts over 141 1/3 innings.