Prospect of the Day: Taijuan Walker, RHP, Seattle Mariners

Taijuan Walker makes his major league debut for the Seattle Mariners tonight. Logically, I have no choice but to make Walker Prospect of the Day, given that he may be the top pitching prospect in baseball right now.

Walker was drafted by the Mariners in the supplemental first round in 2010, from high school in Yucaipa, California. Signed for $800,000, he was considered extremely projectable but rather raw at the time, given that he was mostly a basketball player and shortstop in high school. He looked good in seven feet-wet innings in rookie ball that summer, fanning nine, then moved up to full-season Clinton in the Midwest League in 2011. He posted a 2.98 ERA in 97 innings, with a 113/39 K/BB ratio and only 69 hits allowed. Midwest League sources noted that he looked a lot more polished than they had expected.

The Mariners jumped Walker to Double-A in 2012. The youngest pitcher in the Southern League, he struggled at times and posted a 4.69 ERA for Jackson, but he generally acquitted himself well considering the circumstances, posting a 118/50 K/BB in 127 innings. Returning to Jackson to open 2013, he posted a 2.46 ERA with a 96/30 K/BB in 84 inning with just 58 hits allowed.

Promoted to Triple-A Tacoma at the end of June, he has a 3.61 ERA in 11 starts with a 64/27 K/BB in 57 innings, allowing 54 hits. His ERA would rank sixth in the league if he had enough innings to qualify. Overall, between Jackson and Tacoma he has a 2.93 ERA with a 160/57 K/BB in 141 innings, with 112 hits allowed.

Walker is a 6-4, 210 pound right-hander born August 13, 1992. As you can imagine given his amateur background, he's an excellent all-around athlete who took well to mound work once he moved there full-time. His fastball has been clocked as high as 98 MPH and fits comfortably in the 93-95 range most of the time. Unlike many young power pitchers, he commands the fastball well and hits his locations, not relying on just pure velocity to blow people away.

The key for Walker has been steady development of his secondary pitches. He has a slow curveball, a harder cutter, and a traditional change-up to mix with the heat. The curveball was erratic early in his career but has improved greatly over the last 12 months. The cutter is a new addition to the arsenal but it developed into an out-pitch quickly. His change-up remains his weakest offering but it is useable. At his best, when all four pitches are working, Walker can hit any velocity slot between 70 and 98 MPH.

Walker has an easy and consistent delivery. It is hoped that the combination of his mechanics and his premium athleticism will help him avoid injury. His makeup is considered a positive; he's bright, confident, works hard, is mature for his age, and hasn't looked out of place at all against older competition.

His command is still inconsistent and he's had some high-walk outings lately for Tacoma, walking four hitters in three of his last four starts. Despite that glitch, Walker has had a great season overall, meeting or exceeding all expectations. Assuming all the standard caveats about injuries, Walker has everything necessary to be a top-line starter. He'll probably need some adjustment time, but the physical ingredients and the in-game pitching skills are all here.