Pittsburgh Pirates: Diego Castillo Might Be Best Second Base Option

Pittsburgh Pirates middle infield prospect Diego Castillo is a MLB ready player and could be their best option for second base in 2022

Second base is a questionable position for the Pittsburgh Pirates. Currently, it looks like second base could be a revolving door. Kevin Newman could see some time at the keystone once top prospect Oneil Cruz comes up. Another guy we may see at second base is Hoy Park. Arguably the team’s best prospect is Nick Gonzales.

But none of those options inspire a whole lot of confidence to hold down the fort until Gonzales is MLB ready. But one player that could see time at the keystone is Diego Castillo, who might just be the team’s best MLB-ready second base option.

Castillo had a great breakout season in 2021. Acquired as part of the Clay Holmes trade, Castillo batted .278/.355/.487 with a .366 wOBA, and 128 wRC+ with the New York Yankees’ Double-A affiliate, the Pirates’ Double-A affiliate, and their Triple-A affiliate. Castillo had a massive power burst. He hit 19 home runs with a .209 isolated slugging percentage. He hit just 8 in the previous 5 seasons.

The reason for his power output this year compared to previous years is that his fly ball rate jumped from just 33% to 41.2%. This also means he significantly decreased his ground ball rate. Castillo was mainly a ground ball hitter from 2015-2019 with a 48% rate, but sat at just 38.2%, nearly a 10% decrease.

Coming over to the Pittsburgh Pirates, Castillo was known for his ability to avoid strikeouts. He had just a 10.2% K-rate through his first handful of seasons, but his ability to walk left much to be desired. While he struck out rarely, he also drew ball four just 6.4% of the time. But the change in hitting approach didn’t affect his ability to avoid K’s in 2021. While his 12.7% strikeout rate may be a 2.5% increase, it’s still a phenomenal mark and ranked 28th among the 853 total minor league hitters with at least 300 plate appearances.

To counteract this small increase in strikeouts, Castillo bumped his walk rate up by a fair amount. He drew a walk in 10% of his plate appearances. This made him just one of 21 total minor league hitters to have a sub-15% strikeout rate and 10%+ walk rate in 300+ trips to the plate. He hit for power, got on base, and avoided K’s. By the end of the year, he was at Triple-A where he collected 70 plate appearances in which he had 15 hits, 3 doubles, and home runs, 13 walks, and 13 strikeouts. All told, the small sample size saw him post a 146 wRC+.

Castillo has seen time at shortstop, second base, and third base. He’s an adequate defender at shortstop so he can man second base and third to a good degree of defensive competence. This would give the Bucs a solid defender at the keystone.

Earlier this offseason the Pittsburgh Pirates added Castillo to the 40-man roster to prevent him from becoming a free agent. This puts him on the very cusp of being major league ready. But Castillo isn’t alone in his fight to get the second base job. Aside from Newman, Park, and Chavis, he will have to compete with a few others.

The first is Rodolfo Castro. Castro made his major league debut last year. He’s a power-hitting infield prospect who flashed that power in the majors. 7 of his 17 hits went for extra bases. 5 of which were home runs. However, this was in 93 plate appearances and he struck out 27 times. Castro’s numbers at Double-A are quite awkward. He got off to a phenomenal start to the year but posted a negative wRC+ (yes, negative) in his final 100 plate appearances before he was promoted to Triple-A. At Indianapolis, Castro found his first-half form with 10 hits with 4 doubles and 3 home runs in 38 plate appearances.

Another prospect we could see early into the season is Ji-Hwan Bae. Bae posted solid numbers at Double-A, slashing .278/.359/.413 with a .343 wOBA, and 114 wRC+ at Double-A Altoona. Bae is still young as 2022 will be his age-22 season. But after his decent showing at Altoona, he’ll certainly get things started at Triple-A in 2022. But his young age and this being his first taste of action at Triple-A make him more of a summer call-up rather than an April/May call-up.

One last guy that could threaten Castillo is Tucupita Marcano. Marcano was acquired in the Adam Frazier trade. He skipped High-A, Double-A, and Triple-A and made his major league debut with the San Diego Padres early in the 2021 season. He, understandably, struggled and was sent back to Triple-A.

His numbers at Triple-A don’t jump off the page, but he’s a highly athletic middle infielder with versatility and top-of-the-line hand-eye coordination. Though with his quick and sudden promotion to the majors and then being sent back to Triple-A, Marcano is more than likely a second-half call-up, unless he starts mashing Triple-A pitching (which I wouldn’t rule out), or injuries force the Pirates to promote him.

Once you consider how well Castillo did in the minors, including at Triple-A, his major improvements, and the competition he has, Castillo is probably the organization’s best major league-ready option at second base right now. If he has a strong Spring Training he might earn the job to start as the team’s Opening Day second baseman.