We’ll start at first base and make our way around the horn. The Pittsburgh Pirates best first base prospect is Malcom Nunez. After being acquired by the Pirates at the trade deadline as part of the two-player package for Jose Quintana and Chris Stratton, Nunez batted .280/.385/.475 with a .378 wOBA and 135 wRC+. He hit for his fair share of power with a .195 isolated slugging percentage while having a robust 14.7% walk rate. His strikeout rate of 22.4% was also above average. Nunez is a poor defender at third base but has played a significant amount of first base in the last year, where he could be a playable defender. He also did pretty decently with the Cards’ Double-A affiliate, having a .823 OPS, .367 wOBA, and 110 wRC+.
Aaron Shackelford is coming off a decent season with Double-A Altoona. Shackelford batted .239/.314/.499 with a .351 wOBA, and 117 wRC+. He hit for a ton of power, popping 26 home runs and having a .259 isolated slugging percentage in 443 plate appearances. He also had a decent 9% walk rate. But he also struck out 28.9% of the time. Shackelford can play first base, but he also saw time at second base, left field, and can play some third base. He’s a powerful utility man.
Mason Martin posted his worst career numbers yet. In 541 plate appearances, Martin posted a poor .210/.287/.410 line, .303 wOBA, and 79 wRC+ with Indy. Martin has some of the best power potential in the system and hit 19 home runs with a .200 ISO, but he also struck out 35.9% of the time. He did walk at a 9.6% rate, which was a nice increase from 2021, but it’s been made clear that Martin has a ton of risk. It also doesn’t help that he had an abysmal second half in which his ISO fell to just .158.
Among others at first base, you have Jacob Gonzalez (.836 OPS, .381 wOBA, 132 wRC+), Brendt Citta (.706 OPS, .318 wOBA, 93 wRC+), Will Matthiessen (.532 OPS, .229 wOBA, 37 wRC+), and Ernny Ordonez (.666 OPS, .291 wOBA, 74 wRC+). Only Gonzalez has a chance of being selected out of this group, but even then, since he hasn’t even reached Double-A yet, the chance of him getting picked is not very high.
Both second base and shortstop have very few noteworthy Rule 5 eligible players. They have just one, which is 20-year-old Rayber Romero. Romero did not play in 2022 after testing positive for stanozolol, causing him to miss the entirety of the season. In 2019 and 2021, he was quite the good batter with a .291/.443/.361 line, .408 wOBA, and 138 wRC+. He hit for almost no power, but he had a potent 17.5% walk rate and sub-15% K-rate (13.3%).
On the other side of second base, the only notable Rule 5 eligible prospect is Maikol Escotto. Escotto is coming off a poor season in which he batted just .202/.278/.358 with a .295 wOBA and 77 wRC+. He also struck out just over 30% of the time (30.9%) with a mediocre 7.4% walk rate. Escotto is a solid defender at shortstop but has seen time at second base and third base. He has plus power potential but has yet to piece anything together in an entire season.
Francisco Acuna is the only other Rule 5 eligible shortstop. Acuna did quite well at High-A Greensboro, batting .271/.361/.452, leading to a .371 wOBA and 124 wRC+. Acuna had an 8.8% walk rate and 22.8% strikeout rate, along with a .181 isolated slugging percentage. He’s 22 years old and will likely factor into Altoona’s roster next season.
The hot corner is where we see more notable Rule 5-eligible guys. Jared Triolo is the best among them, having batted .282/.376/.419 with a .356 wOBA and 121 wRC+. Although Triolo turned in just a .136 ISO, he also walked 12.7% of the time with a 17.6% K-rate. Triolo also had a great summer, posting a .878 OPS, .385 wOBA, .194 ISO, and 140 wRC+ from June through the end of the year. Triolo is arguably the best defensive infield prospect the Pirates have to offer. He’s a third baseman by trade but can play shortstop and center field.
Dariel Lopez is another infield prospect coming off a solid campaign. He batted .286/.329/.476, owned a .359 wOBA, and 116 wRC+. Lopez crushed 19 home runs while having a .189 ISO. On the downside, he only walked 5% of the time with a 25.5% K-rate. Like Triolo, Lopez also enjoyed a fun summer, having a .859 OPS, .382 wOBA, and 131 wRC+ from June through the end of 2022. Lopez mostly played third base but has played an ample amount of time in the middle infield. He’ll likely end up at first base because of his sub-par range and overall fielding prowess at third and the middle infield.
Andres Alvarez (.789 OPS, .342 wOBA, 111 wRC+), Juan Jerez (.647 OPS, .306 wOBA, and 86 wRC+), Alexander Mojica (.607 OPS, .297 wOBA, 90 wRC+), and Luis Tejada (.885 OPS, .446 wOBA, 173 wRC+) are the rest of the third base minor leaguers who will be Rule 5 eligible. Alvarez has a chance of being picked. This year, he was a 20/20 batter who provided playable defense at the hot corner, both middle infield positions and left field. But, like Jacob Gonzalez, it is far from a guarantee to be selected.