For the first time since 2017, the Minnesota Twins selected a player in the Rule 5 Draft. The team selected Philadelphia Phillies minor league pitcher Eiberson Castellano as their first and only Rule 5 pick this winter. It may be a surprising move, given that in the Derek Falvey era, the Twins had only selected one Rule 5 player before when they took Miami Marlins reliever Tyler Kinley.
Minnesota’s circumstances entering the Rule 5 draft made it the right time for the Twins to use a pick on the right-handed starting pitcher from Venezuela.
First, given Minnesota’s limited payroll, they will probably have to dump salary before signing a free agent. Last year, the Twins tried to bolster their bullpen via free agency. They added Jay Jackson and Josh Staumont, who they cut before the end of the season. However, like most Rule 5 picks, Castellano is more of a long-term play than a short-term one.
According to MLB.com, he slides in at No. 13 in Minnesota’s farm system. Castellano is coming off a breakout season in the Phillies system. From the outside, it’s surprising that Philadelphia didn’t protect him. Instead, they protected Jean Cabrera.
Castellano appeared in 22 games and started 20 of them. He put together a 3.99 ERA over 103.2 innings between High-A and Double-A last season. It’s a modest clip for someone in the lower minors. Still, his underlying metrics make him an interesting selection for the Twins.
His ERA may seem high for someone who won Philadelphia’s Minor League Player of the Year. However, Castellano showcased his ability to generate swings and misses consistently, with 136 strikeouts over 103.2 innings. He also struck out batters without sacrificing his command. Castellano recorded a career-best 4.69 K/BB clip in both levels in 2024. His 2.8 BB/9 mark in High-A improved to a 2.0 BB/9 record in Double-A while keeping his 11.2 K/9 rate the same in each level of the minors.
Castellano can improve his K/BB ratio with better command of his pitching repertoire. His pitch mix consists of a 4-seam fastball, a changeup, and a curveball. Castellano’s mid-90s fastball will be helpful for the Twins, especially if they can maximize his extension and increase his velocity a tick or two like the Twins have for other arms like Bailey Ober.
Scouts believe Castellano’s changeup is the best secondary pitch. Whether Castellano develops his curveball will indicate if he can stick as a starter or stay in the bullpen. Scouts consider his breaking ball raw, although potentially impactful. Therefore, the Twins will likely tweak his pitch mix when they start to work with him.
The risk in drafting Castellano is that he had his first big run of success in the minors last year. Before this season, he never got an ERA better than 4.00 in the minors. Furthermore, Castellano gave up a career-high 1 HR/9 in 2024. The Twins will monitor that as he jumps to the majors next year. They are likely banking on his talent and the ability to use him in limited situations from the bullpen to protect Castellano through his upcoming rookie season.
One of the factors that makes the Rule 5 Draft so complicated but intriguing is that the player selected has to spend the entire season on the major league roster. Instead of optioning them to the minors, the team that drafted them must return them to their original team.
For example, Kinley appeared in only four games for the Twins in 2018. After allowing nine runs over 3.1 innings, Kinley was sent back to Miami. Therefore, teams using a Rule 5 pick must calculate the logistical risk of putting a player on the roster.
It’s why even though Castellano has been primarily a starter in the minors, he will move to the bullpen for 2024 to be more deliberate as a multi-inning reliever in 2025. However, Falvey hinted that he could become a starter after the 2025 season. It’s the path Johan Santana took in his first season in Minnesota in 2000 after arriving as a Rule 5 pick in 1999 following a trade with the Marlins. However, for every Santana, hundreds, if not thousands, more Kinley-type exchanges happen.
That’s likely why the Twins hesitate to use Rule 5 picks. It’s a gamble to lock up a roster spot for an unproven reliever, especially for a Twins team that values bullpen flexibility. It could be an issue if Castellano struggles.
Furthermore, if he throws two or three innings in an appearance, Minnesota would typically option that player to Triple-A so they can rest in the minors and make a fresher arm available for Rocco Baldelli. However, the Twins must be committed to keeping him on the roster.
With this move, the bullpen ecosystem gets its first shakeup of the winter. Assuming the Twins carry 13 pitchers on their roster and 5 of those spots will be in the starting rotation, below is a rough early outlook for the 2025 bullpen.
Sands earned the opportunity to pitch in more high-leverage situations last year, opening a spot in the bullpen hierarchy for a multi-inning pitcher to be a “clean-up” arm. As a Rule 5 pick, Castellano is best suited for a low-leverage, innings-eating role to start. The Twins probably won’t use him often this coming season. However, he’ll be available in case of a blowout and can acclimate to the majors while still working behind the scenes with the big league club.
Castellano’s production last season makes it a good bet for the Twins to gamble on in 2025. They potentially landed a young, team-controlled reliever. In the best-case scenario, he could develop into a starting pitcher, creating more depth for the organization at a premium position.
Castellano is a young pitcher who has shown a sample of what he can offer to a major league club. Coming in as the team’s first Rule 5 pick since 2017, he will need to continue the development he showed was possible last season to become the pitcher the Twins envision. Rule 5 picks can be a logistical hassle. However, Castellano has the upside, making him a good bet to stick in the big leagues with the Twins.
