The Pirates' best under-20 catching prospect is Axiel Plaz, who could eventually become one of the team's best prospects. Plaz is just 17 and won't turn 18 until August 12th. Plaz's first look at the Dominican Summer League could not have gone any better. It was only 86 plate appearances, but the young backstop batted .382/.500/.706, with a wOBA clocking in at .550 and wRC+ over 200 at 209. He racked up three home runs, an impressive amount of doubles (11) with a 13:16 BB:K ratio.
Plaz has already gained some prospect notoriety, as Baseball America ranked him as the Bucs' 28th-best prospect. Plaz's defense was considered his strong suit, but with decent offensive upside. It will be interesting to see how Plaz develops going forward.
The best overall infield prospect the Pirates have is Termarr Johnson. Johnson was the team's first-round draft pick from this past season. He was considered one of the best prep hitters in recent draft history, with MLB Pipeline comparing his plate discipline and plate coverage to Wade Boggs and Vladimir Guerrero Sr., respectively. He also runs well, and don't let his 5'7", 175 pounds stature fool you. He hits for above-average to well above-average power because of his lightning-quick bat speed.
Johnson is a guy who could consistently hit .300/.400/.500 each season. He also has the speed and power to be a 20/20 guy, at least. The only question is what middle infield position he'll play long-term. Johnson makes the routine plays at shortstop, but his arm is fringy at best, and he will have some difficulty making some of the deeper plays. The Pirates drafted him as a shortstop, and although he played some short in his first look against professional opponents, he mostly lined up at the keystone.
One of the most interesting prospects the Pirates have to offer is Tony Blanco Jr. The Pirates signed the young outfield prospect during the 2021-2022 international signing period, and he comes with the power potential of someone like Giancarlo Stanton. Blanco Jr. already stands at 6'4", 245-LBS before his 18th birthday (currently 17 and won't turn 18 until May 14th). Speaking of Stanton, that is the same weight Baseball Reference currently lists the Yankees' DH/OF at, and just two inches taller. That kind of size gives him a sky-high ceiling but a risky floor.
Blanco struck out ten times in his injury-shortened 19 plate appearances at the DSL. He's already not considered a fast base runner, but he does at least have an arm to play an outfield corner. Granted, even Stanton was considered average to above average in terms of speed in his first handful of seasons. But depending on how Blanco develops, he might have to move to first base long-term.
The third player on this list the Pirates signed out of the 2021-2022 international market is Yordany De Los Santos. The infielder slashed .258/.372/.363 with a .368 wOBA and 106 wRC+ through 234 plate appearances at the Dominican Summer League. De Los Santos had a strong 13.7% walk rate and 19.2% walk rate but did not hit for much power. He only bopped one home run and had an ISO of .105. He also had nearly as many walks (23) as strikeouts (24) and a 130 wRC+ from July 9th through the end of the year.
Despite his low power output in his first look at the DSL, De Los Santos projects to have 60-grade power, per FanGraphs. His hit tool also comes out to about average, but like Johnson, his final position is yet to be determined. There's some concern that once he fills out his 6'1", 170 pounds frame, he'll have some trouble with his range at shortstop. He certainly has the arm to play on the left side of the infield, and on the plus side, he did show some improvements in terms of defense last season. If he can continue to make those improvements and keep his range up, he won't have to move off of shortstop.
Shalin Polanco is the longest-tenured player we'll look at today. The Pirates signed Polanco as an international signee in the 2020-2021 off-season. Polanco has spent the last two seasons with the Pirates' short-season affiliates (DSL and FCL), turning in a mediocre .225/.303/.353 line, .320 wOBA, and 86 wRC+. He's walked at a respectable 9.3% rate but has struck out just over a quarter of the time (25.3% K-rate) and has an isolated slugging percentage of .128.
MLB Pipeline is still bullish on the left-handed hitting outfielder, however. He's still a projectable 5'11", 168 pounds, and has shown off some decent bat speed. If he can add some muscle behind that bat speed, Polanco could end up with above-average game power. He also grades out as an average to above-average runner and defender with a solid arm. He's shown off an overly aggressive approach at the plate, leading to a higher strikeout rate.