With pitchers Hisashi Iwakuma, Taijuan Walker and Stephen Pryor all sidelined, the Mariners signed Young on Thursday after he was released by Washington. The 34-year-old right-hander allowed four hits, struck out two and issued no walks in 4 2-3 innings as he moves into a rotation spot.
Kyle Seager's RBI single in the second was the lone run off Rockies starter Franklin Morales. He worked around five walks and three hits in 5 1-3 innings, a day after he was selected as the fifth starter.
Seattle newcomer Robinson Cano struck out and flied out before exiting in the third, finishing with a .412 spring average.
The Mariners open the regular season against the Angels in Anaheim on Monday.