MLB trade deadline: Marlins, D-Backs swap Zac Gallen for Jazz Chisholm in rare prospect-for-prospect trade

Chisholm has struggled this year, but he is one of the game's top prospects

The 2019 trade deadline featured a rare prospect-for-prospect trade. On Wednesday, the Miami Marlins sent right-hander Zac Gallen to the Arizona Diamondbacks for infielder Jazz Chisholm, both teams announced.

"I'll forever be grateful to the Marlins for giving me the opportunity to make my debut. Getting to the big leagues is always something I've wanted to do," Gallen told reporters, including MLB.com's Joe Frisaro, following the trade. "Any time you can open some eyes and do what you can, it's good for your career. I'm excited."

Gallen, 23, tore up Triple-A this season before making his MLB debut with the Marlins on June 20. Between Triple-A and MLB, he has a 2.04 ERA with 155 strikeouts in 127 2/3 innings. The 2016 third round pick has been great wherever he's pitched.

MLB.com does not rank Gallen among their top 100 prospects -- he is technically still a prospect because he's yet to exceed the 50-inning rookie limit -- but they do rank him as the fifth-best prospect in Miami's system. Here's part of their scouting report:

His upper-80s cutter is his bread-and-butter pitch, and he works it to both sides of the plate with the ability to backdoor it for strikes against left-handers. His low-90s fastball has added a tick or two of velocity this year, now topping out at 95 and playing up because he creates downward plane and locates it so well ... Gallen also keeps hitters off balance by varying the speed on his changeup and curveball, with the latter a slightly better offering ... He has one of the highest floors among the organization's pitching prospects and his ceiling appears higher than Miami initially expected.

Chisholm, 21, came into the season as one of the top prospects in the game, and MLB.com currently ranks him as the 59th best prospect in baseball. He has struggled this season though, hitting .204/.305/.427 with 123 strikeouts in 89 games at Double-A. Still, Chisholm has star-caliber tools. Here is a snippet of MLB.com's scouting report:

Chisholm posts impressive exit velocities from the left side of the plate with an explosive swing that has natural loft ... Chisholm's power does come with swing-and-miss tendencies, so he'll need to refine his aggressive approach as he develops. He's an above-average runner who receives praise for his instincts on the basepaths ... There is little question Chisholm can stay at shortstop, with good hands and actions to go along with a strong arm and a knack for making highlight-reel plays on a nightly basis. Those loud tools on both sides of the ball in turn give Chisholm an exceptional ceiling as a big league shortstop, but he'll need to tighten up his overall game along the way.

Prospect-for-prospect trades are rare because everyone loves their kids more than everyone else's. In this case, it appears the Marlins believe they are selling high on Gallen and buying low on Chisholm, a player with high-end ability. The D-Backs, meanwhile, may believe they're cashing Chisholm in as a trade chip before his value drops further following a down year.