Walters tossed 1.2 scoreless innings and did not factor into the decision in Wednesday's 5-2 win over the Guardians.
Walters served as the opener in a bullpen game and retired all five batters he faced while throwing 13 of 20 pitches for strikes. The 23-year-old has not surrendered a hit or earned run through his first 7.2 major-league innings while posting a 6:4 K:BB.