Where does infielder Leo Rivas fit with the Seattle Mariners in 2026?
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Following the Mariners' acquisition of highly sought-after infielder Brendan Donovan, it answers a lot of questions about the team's lineup and defensive play in 2026. However, it may have opened up one for third-year player Leo Rivas.
While Seattle is set at second base now, the only wide-open starting spot is at third base. Eugenio Suarez signed with Cincinnati. Many fans and observers thought it would be youngsters Ben Williamson and the team's top prospect, 20-year-old Colt Emerson, who would fight it out in Spring Training.
But with Williamson part of the Donovan deal, it appears that the Mariners believe in Emerson that much. He's gone from a roster hopeful to a frontrunner for a starting spot. At the same time, the kid hasn't swung a bat in a Major League game yet. Through no action of his own, the promising prospect may fall into the role, based on the team's needs.
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Right now, Miles Mastrobuoni is penciled in at the top of the M's depth chart at third, but he's 31 years old and has only had 399 at-bats in MLB. With all due respect to him, he's a former 14th-round draft pick and essentially a '4A' player. There's no way he will be the starter.
But what about Leo Rivas? While it seems anticlimactic now that Emerson will be on the roster, he needs to face veteran competition in camp. Yes, the team has other candidates who could start there, but Rivas and Emerson (both natural shortstops who are versatile enough to move around the infield) should be the top two hot corner hopefuls as the team prepares for their annual Arizona pre-season.
Rivas is an outstanding, versatile defender
Rivas has put up paltry numbers since he debuted in 2024, with just a .239 batting average, two home runs, and 17 RBI. However, he has Major League Baseball experience with a winning team, which is a huge variable that you can't measure. The M's infielder has top-notch fielding skills, and that could be an excuse to bring Colt Emerson along slowly - as a utility, bench player
Rivas is considered a reliable infielder for the Mariners. In 2025, he had a fielding percentage of .990 over 48 games, and in the postseason, he maintained a perfect 1.000 in the category. Analysts and media praise his dependable defense, even if he’s not flashy.
After two seasons where he's only partially played, Rivas has proven he's a legitimate big-leaguer, but is he merely a career back-up, or can he fill an everyday role? That's a question that Seattle will hopefully find out in the next few weeks.
