Mariners call up prospect SF Giants traded for Donovan Walton
The Seattle Mariners called up former Minnesota Twins and SF Giants prospect Prelander Berroa to their big-league roster on Wednesday, just over a year after acquiring him from the Giants in exchange for infielder Donovan Walton. Berroa has been one of the most electric arms in the minor leagues and was ranked as the number ten prospect in the Mariners organization according to Baseball America's latest top 30 rankings. Prior to the season, one scout called the Giants decision to trade Berroa for Walton the worst deal of 2022.
Berroa repeated the Double-A level this year for the Mariners and was deployed as a starter early this season, but he walked 18.5% of the batters he faced in his first five starts. His struggles with control prompted the Mariners staff to shift him into the bullpen as a late-inning arm. The decision quickly paid off. Since the move, Berroa has a 0.77 ERA and 35 strikeouts in 23.1 innings. More importantly, he saw his walk rate drop to a more manageable 13.5% rate while also earning a couple of saves. His strike-throwing improvements were enough for the Mariners to have him skip Triple-A altogether and head to the majors.
The Giants acquired Berroa from the Minnesota Twins alongside Jaylin Davis and Kai-Wei Teng for Sam Dyson at the 2019 MLB trade deadline. Berroa had not pitched outside of short-season ball, but had showcased high-90s velocity and an intriguing breaking ball.
After the pandemic-canceled 2020 minor-league season, Berroa struck out 135 hitters in 98.2 innings pitched with a 3.56 ERA at Single-A in 2021. Berroa did struggle with control, walking 53 hitters over the course of the season. Still, he showcased an impressive ability to maintain upper-90s velocity on his fastball alongside a nasty slider and developing changeup.
Berroa moved up to High-A in 2022, and despite being more than a year younger than the average player in the league, he continued racking up strikeouts and limiting opposing runs. He struck out 16 hitters in 13.1 innings while allowing just one run before the Giants traded him to the Mariners for Walton.
Berroa made 13 more starts with the Mariners' High-A affiliate before he was promoted to Double-A. Over that span, Berroa struck out nearly 40% of the batters he faced and had a 2.41 ERA. His walk rate remained high (14.9%), but was far from enough to overshadow his dominance as a 22-year-old.
At Double-A, Berroa's walk rate spiked even further, driving his ERA up to 4.37. However, he still struck out 53 hitters in 35 innings pitched at the hitter-friendly Texas League.
To make matters worse for the Giants, Walton's tenure in San Francisco has been a struggle to watch. While he hit roughly .300 with a slugging percentage north of .500 from 2021-22 at Triple-A with the Mariners, he hit just .158/.179/.303 in 78 plate appearances with the Giants.
Walton was also atrocious defensively at shortstop. While he only made two errors in 13 games in place of Brandon Crawford, he amassed three outs below average at the position, per Outs Above Average.
Eventually optioned to Triple-A, Walton was unable to pick up where he left off. He posted a measly .225/.345/.358 triple-slash in 20 games with the Sacramento River Cats. Given his struggles, the Giants designated Walton for assignment and outrighted him to the minors.
Walton re-signed a minor-league contract with the Giants this offseason. His deal included an invitation to big-league camp, but he got hurt before the 2023 season started and did not start his season until mid-June at the ACL for his rehab stint. He is continuing his journey back to Triple-A with him currently playing for Double-A Richmond. However, it seems highly unlikely that Walton will make a contribution in the majors for the SF Giants. Barring something unforeseen, Farhan Zaidi's decision to trade Prelander Berroa for Donovan Walton could one day rank among one of the worst moves of his tenure.
