Mariners top prospect pitcher Taijuan Walker stretched a scoreless innings streak to 14 before he allowed a solo homer in the fourth inning of Sunday's start with Triple-A Tacoma, his third at this level, MLB.com reports.

Walker took the no-decision after going five innings with six hits and just the lone run allowed. The 20-year-old has gone 2-0 with a 0.56 ERA with five walks and 16 Ks over 16 innings while holding opponents to a .186 average thus far.