Rodolfo Castro will open the year as the Pirates' second baseman. Castro secured the keystone in the second half of last year, specifically after the Bucs recalled him in early August. Castro ended the season on a very high note, batting .251/.311/.486 from August 10th through the last game of the year. Castro had a roughly average 8.2% walk rate along with a robust .235 isolated slugging percentage in 196 plate appearances. Among players with 180+ trips to the dish in this stretch, he was tied with Jose Ramirez and Christian Walker in ISO. The only red flag in Castro's offense was his 28.1% K%, but overall, he had a .343 wOBA and 121 wRC+.
As a defensive second baseman, he's not great, to say the least. The young infielder has never been known for his glovework, and last year he had -2 defensive runs saved, a -9.2 UZR/150, and -3 outs above average in just 236 innings up the middle. His best position defensively last year was third base, but he's not going to push Ke'Bryan Hayes anywhere anytime soon.
Even though Castro had a good season overall, he could still be overtaken by what I consider the Pirates' most underappreciated prospect, Nick Gonzales. Last year, Gonzales batted .263/.383/.429. Gonzales hit for decent pop with a .166 isolated slugging percentage, and he drew walks at a 13.6% clip. However, the downside is he struck out 28.5% of the time. While his strikeout rate was unimpressive, he still had a quality .365 wOBA, and 127 wRC+/
While his strikeout rate isn't good, it's explainable. Gonzales has gotten off to a slow start in each of the last two seasons. In 2022, he had just a .180/.324/.292 line and 80 wRC+ through May 10th. During this time, he struck out 37% of the time. After May 10th, he hit .306/.411/.506 with a 151 wRC+ and a much more manageable 24.2% K-rate. That still needs improvement, but Gonzales missed all of June and July. When he returned to baseball in early August, he would only strike out 22.7% of the time from there on out. He cut his strikeout rate even further to 20.7% through the final month of the minor league season.
Gonzales isn't considered the next Bill Mazeroski when it comes to fielding, but he holds his own at the keystone. He's also seen time at shortstop at Altoona and third base in the Arizona Fall League, but second base is his home. He may only see time at shortstop or third base if there is an injury and he's forced to play the position.