To clear a spot on the 40-man roster, which was at capacity, the Mariners designated for assignment catcher Nick Raposo. He was one of their external 40-man additions this offseason after being claimed off waivers from the Blue Jays on Dec. 19. Seattle has seven days to trade, release or outright Raposo to the Minors.
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Mastrobuoni, 29, has been a part-timer in the Majors for the past three seasons, including the past two with the Cubs. His career slash line over 272 plate appearances is .219/.279/.263 (.542 OPS), which includes one homer, eight doubles and nine RBIs across 119 games, with 55 strikeouts and 21 walks. He’s also stolen 16 bases in 17 attempts.
His numbers in the upper Minors have been much better and over a lengthier sample. In 982 plate appearances at the Triple-A level from 2022-24, Mastrobuoni slashed .278/.371/.434 (.805 OPS) with an 18.1% strikeout rate and 12.8% walk rate, good for a 114 wRC+ (league average is 100).
The Mariners acquired Mastrobuoni for his defensive versatility. He has played at third base, second base and shortstop and in the corner-outfield spots in the Majors. He also has one Minor League option remaining, adding to his roster value.
Seattle has been seeking infielders all offseason, and the club remains in the market for a more impactful addition than Mastrobuoni. The Mariners’ first major move, albeit one that wasn’t at the upper echelon of free agency, was signing veteran infielder Donovan Solano to a one-year, $3.5 million contract on Monday.
Mastrobuoni was DFA’d by the Cubs last Thursday when they acquired former Mariners reliever Matt Festa from Texas.
