Mariners utility man's inexplicably hot spring could complicate roster plans

The Mariners' offseason was almost entirely driven by a need to strengthen the infield. Outside of shortstop, there was a total lack of compelling candidates. After the front office went out and acquired Josh Naylor and Brendan Donovan, the outlook improved but was still imperfect. With the corner infield positions taken, there was still uncertainty on who would be playing second base.

For now, Seattle seems to have placed their hopes on Cole Young, who still has plenty to prove. There are other players vying for the starting spot. The potential of Colt Emerson being called up is a hotly debated topic and Donovan's primary position has been second base since 2022. This talented trio was originally slated to be the future of the infield, but a new challenger has forced himself into the conversation with his performance in spring training so far.

Miles Mastrobuoni has been one of Seattle's hottest players in spring training thus far

Mastrobuoni is just one of three players to appear in all five of the Mariners' spring training games and he has made the most out of the opportunity, posting a .917 OPS over his 12 plate appearances. It's a small sample of spring training appearances but it's difficult not to get at least a little excited.

He's primarily known for being a utility defender with a decent glove at nearly any position. Offensively, he's never really brought much to the table. He has never made more than 175 plate appearances in a single season and has a career OPS+ of 64.

His Statcast metrics are more encouraging than his slash line would suggest. At 5-foot-10 and 185 pounds, his batting profile is similar to other players with leaner builds. His bat speed and average exit velocity are both comfortably below-average, but his ability to square up baseballs consistently helps compensate for a lack of brute force. Unfortunately, his .296 slugging percentage last year simply won't suffice at the big league level.

One big improvement to his approach that could take his game to a whole new level would be to pull the ball in the air more often. This has allowed players with similar physical profiles like Mookie Betts to post impressive slugging numbers despite similarly limited bat speed. Mastrobuoni has a career pulled fly ball rate of just 9.2, nearly half the MLB average of 16.7 percent. He already squares up the ball at an elite rate — getting out in front would reward him even more for doing what he does best.

Through it all, Mastrobuoni has maintained his focus and is determined to do his best to earn a spot on what's shaping up to be a very competitive roster. With two doubles and a home run in just 12 plate appearances, he has demonstrated that he is capable of producing meaningful pop. Now he just needs to prove that he can do that against big league pitching.

If the next month continues to go his way, the Mariners will be forced to face a tough albeit good problem to have. Having an excess of infield talent may have seemed unlikely just a few months ago yet with Seattle's knack for player development, you just never know who will be the next guy to step up. Miles Mastrobuoni may not carry the same prospect pedigree as Cole Young or Colt Emerson, but his impact on the field could simply be too good for the team to ignore.