Top prospect Walker to make first MLB start on Friday

SEATTLE -- The long-anticipated arrival of Taijuan Walker in the Major Leagues will occur on Friday in Houston. When he makes the start, Walker will be just 21 years, 17 days old, making him the fifth-youngest starter in team history.

Current ace Felix Hernandez was the youngest player to start a game for Seattle, when he allowed just one earned run in five innings as a 19-year-old in 2005.

Walker will wear No. 27 for Seattle, which will make the official roster move on Friday prior to the 5:10 p.m. PT game against the Astros at Minute Maid Park. The 6-foot-4, 210-pound righty is the No. 4 prospect in baseball, according to MLB.com, and No. 1 in the Mariners' system.

Walker, who hails from Yucaipa, Calif., was selected by Seattle in the supplemental first round (43rd overall) of the 2010 Draft. He has quickly risen through the farm system, beginning the year in Double-A and getting promoted to Triple-A after just 14 starts.

After 11 starts with Tacoma, the Mariners decided they had seen enough to promote Walker, as he went 5-3 with a 3.61 ERA with 64 strikeouts in 57 1/3 innings. He is currently tied for fourth among Minor League pitchers with 160 strikeouts on the season.