Willi Castro's Unique Skill Set Makes Him Irreplaceable on Current Roster

“Willi’s is the key to all this.” – Rocco Baldelli, probably.

On Monday, the Twins announced that Royce Lewis would be making his return from an oblique injury that had him sidelined since July 1st. The bad news was that Willi Castro would hit the injured list with an oblique injury of his own—through a lesser strain than the one that sidelined Lewis for six weeks.

Castro was a mere afterthought at the season’s onset—a non-roster invitee on a minor-league contract. However, the Twins saw something in the then-25-year-old, as the contract was worth $1.8 million.

Castro wasn’t a standard minor league signing, as he still had three full years of team control after spending parts of four seasons in Detroit. If the toolsy, versatile player could carve out a role on the MLB team, he would be quite the asset.

He carved out a role he has, but it wasn’t apparent that he would.

Originally added to the active roster ahead of Opening Day as a placeholder for injured players Jorge Polanco and Alex Kirilloff, Castro didn’t see any action until the end of the fourth game of the year, replacing Carlos Correa in an 11-1 blowout against the Marlins. Through 10 games, he had played in four—starting only three.

On some teams, that usage would be expected of the last guy on the bench, but it’s undoubtedly not Baldelli’s style. It probably indicated that the team saw him as a non-factor, break-glass-in-case-of-emergency option with his switch-hitting and ability to play anywhere.

He played more as the season went along, generally used as a late-game replacement. Through May 11th (37 games), he had appeared in 26 games, starting only 12, and entered the game in the seventh inning or later 12 times. He also struggled, posting a .186/.300/.302 (.602) slash line with one home run in 50 plate appearances.

His name was often thrown around by commentators as a candidate for demotion whenever another player returned from the injured list. Somehow—mainly as a result of other players on the active roster getting hurt before he headed to the chopping block—he kept his spot with the big league team.

He also got hot at the right time. From April 30th to June 1st, he was one of the few bright spots on a team struggling offensively, slashing .329/.358/.500 (.858), stealing 10 bases in 11 attempts and playing six positions. Through that stretch, he managed to carve out a niche and, since, has rarely had his role questioned.

Baldelli has also grown attached to utilizing his skillset. One might even say that Castro is the key to all of Baldelli’s chicanery this season. He has become infamous—or famous, depending on your stance—for tinkering in-game and playing matchups. Castro brings several skills that can help in these endeavors.

First, he can play everywhere. In 2023, he has appeared at third base, second base, shortstop, all three outfield positions, and even pitcher on two occasions, drawing starts at all those positions other than shortstop and pitcher. If there’s a hole in the lineup card, Castro can fill it.

He’s also a switch-hitter, which allows him to start games in the outfield against left-handed starters, giving one of the left-handed Twins corner outfielders a break. He’s posted a meager .670 OPS against left-handed starters, but he fills the role that Baldelli seeks.

Those bits are good, but he mainly enables Baldelli’s deepest, darkest impulses after the first pitch has been thrown. Castro is the Band-Aid to any move Baldelli wants to make.

If Baldelli wants to pinch-hit Donovan Solano for Max Kepler against a tough lefty reliever, he can move Castro from third base to right field. If he wants to hit Edouard Julien for Michael A. Taylor, Castro can move from second base to center field to make it happen. Are Kepler, Kirilloff, Joey Gallo, Trevor Larnach, and Matt Wallner suddenly all in the lineup together? No worries, just sub Castro in for one of them and put him wherever the open spot in the defense is.

Sure, Castro has had his share of pinch-hitting himself, as he’s pinch-hit 11 times, but he’s more likely to solve problems caused by other substitutions. He’s also pinch-run nine times, and his 29 stolen bases in 33 tries have also been a valuable asset.

He’s been put to use whether he starts or enters later in the game. In fact, between May 10th and July 16th, he played in 54 of 56 games, starting only 41 of them. There have only been 22 games, as of August 18th, that Castro hasn’t played at all. Five of those games have been since his injury. He’s played 101 of 123 games but only started 71 of them. He has entered the game late or switched positions in the field 59 times this season.

He’s also thrived in the role, relatively. The bar will always be lower for a role player like Castro. Still, he’s stolen bases at a remarkable clip and has a respectable (for a utility player) 94 wRC+ (six percent below an average hitter). He’s provided solid defense at each position he’s played (OAA and DRS both have him at a -2 in center field, his lowest ratings, but he only had 121 MLB innings before 2023 and hasn’t been bad there).

He’s certainly been worth the $1.8 million paycheck. Baseball-Reference and FanGraphs project him to finish with a WAR around 2, about a league-average starter, though his injury may offset that.

For comparison, consider a player like Marwin Gonzalez, tabbed as a high-end super-utility player in 2019 and 2020. Gonzalez played a crucial role in the 2019 season, putting up an OPS+ of 94, right on par with Castro this year. Castro beats Gonzalez out in defensive versatility and base running, though. The Twins gladly paid Gonzalez $12 million that year, seven times what Castro was paid for 2023.

Pound-for-pound Castro’s signing probably resulted in the best value that the team got this offseason. Competent Swiss Army knives are difficult to find (look no further than the extended look that Willians Astudillo got), and Castro has filled that role better than almost anyone would have expected. No one would say he’s a top-15 player on the team, but he’s done his job.

At no point during the offseason would anyone have expected Willi Castro’s presence to be so valuable, but Baldelli will be hamstrung in the coming weeks without his Get Out Of Lineup Jail Free card. If you believe his moving and shaking is more than it’s worth, maybe the injury will relieve you, but Baldelli will need to think a little harder for now.