O'Malley is the early favorite for the Mariners' utility spot entering spring training, Greg Johns of MLB.com reports.
The 29-year-old has seen action in 113 games over the last two seasons in Seattle and slashed .229/.299/.319 with nine doubles, two triples, two homers and 17 RBI in 2016. Last season, the switch-hitter was deployed at second base, third base and shortstop while also seeing action at all three outfield positions. His versatility and experience give him the early edge, but O'Malley could be pushed by newcomer Taylor Motter and Mike Freeman.