SF Giants: Prelander Berroa adding insult to injury for Donovan Walton trade

The SF Giants traded right-handed pitching prospect Prelander Berroa to the Seattle Mariners for infielder Donovan Walton earlier this season. While Walton immediately struggled with the Giants before suffering a season-ending shoulder injury, Berroa has excelled in the minors with the Mariners and is starting to get national attention. It's hard to imagine the Giants would not do some things differently if they could go back and undo the deal.

Berroa was signed as an international free agent by the Minnesota Twins in the 2015-16 International Free-Agent window. Berroa showed off a big arm in Rookie Ball with the Twins but struggled to locate his pitches. Still, Giants scouts liked what they saw and acquired Berroa as part of a three-player package they received from the Twins for reliever Sam Dyson at the 2019 MLB trade deadline.

Berroa struggled to wrap up the 2019 season and then was forced to work on his game from home when the COVID-19 pandemic led to the cancellation of the 2020 minor-league season. However, even without a season, Berroa clearly made strides over that period.

When Berroa returned to the minors in 2021, he was assigned to Single-A San Jose. In his first year at full-season ball, Berroa struck out 135 hitters in 98.2 innings pitched with a 3.56 ERA. Berroa did walk 53 hitters over the course of the season. Still, he also showcased an impressive ability to maintain his 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. In his first four starts of the season, Berroa surrendered just one run across 13 innings pitched while racking up 16 strikeouts and six walks. Then, the Giants sent him to Seattle 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 37.7% 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 has increased to 16.7% over his 31 innings pitched (eight starts), but he has maintained a solid 3.77 ERA in the hitter-friendly Texas League environments (the league has a 5.12 ERA this season). Despite facing more advanced competition, Berroa is still striking out nearly 35% of opposing hitters and is showing no signs of becoming any more hittable. His arsenal of pitches is just that good.

Berroa has quickly become a consensus top-20 prospect in the Mariners organization, but that may be just the beginning of his stock's rise. Tieran Alexander wrote an excellent piece for Prospects Live about Berroa's eerie similarities to Cleveland Guardians pitching prospect Daniel Espino, considered a consensus top-25 prospect in the minor leagues.

Alexander breaks down the two prospects' pitch data and shows that they both have some of the best pitch arsenals in the minors. While Berroa's command lags behind Espino's, Alexander believes his problems are fixable. If he's right, and Berroa can corral his command, Berroa could become one of the best pitchers in MLB.

Walton's time since the trade has not gone as favorably for the team that acquired him. He had impressive Triple-A numbers with the Mariners over the past two seasons (hitting .304/.395/.519 in 2021 and .294/.368/.510 in 2022), and the Giants immediately called on Walton to contribute on their big-league infield while they were dealing with injuries.

Manager Gabe Kapler deployed Walton primarily at second base and shortstop. He simply looked terrible at short. While he only made two errors in 13 games in place of Brandon Crawford, he was already graded three outs below average at the position by Statcast.

Making matters worse, Walton looked completely overmatched at the plate. In 78 plate appearances with the Giants, Walton managed eight doubles and one home run but recorded an abysmal .158/.180/.303 triple slash. Struggling to add any value in the field or at the plate, Walton was eventually optioned to Triple-A Sacramento.

There, Walton's previous upper minor-league success disappeared. While he had an excellent strikeout (13) to walk (12) rate, Walton hit just .225/.345/.358 in 20 games with the River Cats.

His defensive struggles at shortstop may have been an early sign of the right-shoulder injury that ended his season. However, Walton is already 28. Will the Giants be willing to keep such an unproven big-league contributor on the 40-man roster all offseason? If not, they could have nothing left to show for Berroa.

SF Giants president of baseball operations Farhan Zaidi rightfully deserves some praise for his trade with the Mets at the deadline that already looks like a steal. With that said, as Prelander Berroa continues racking up strikeouts at Double-A and Donovan Walton rehabs an injury to his throwing shoulder, Zaidi probably wishes he could undo that minor trade with the Mariners.