O'Malley (shoulder) went 2-for-2 with a triple, three walks and three runs as the designated hitter for Rookie-level Arizona on Saturday, Greg Johns of MLB.com reports.
The utility man couldn't have asked for a better 2017 debut, and is likely in for at least several more games at the Rookie level before taking his rehab up the organizational ranks. O'Malley slashed .229/.299/.319 with two home runs and 17 RBI over 89 games with the Mariners last season in what was his first taste of extended big-league action. If he remains free of setbacks, O'Malley should be cleared for a return to the big-league club at some point next month, although how much playing time he'll see will largely depend on the club's injury situation at the time.