When the Yankees designated Stephen Tarpley for assignment to make room for Brett Gardner, there was little doubt he was going to become a target for somebody. A hard-throwing left-handed pitcher who shows the ability to miss bats is a pitcher that many teams would love to add to their organization, as long as they have the 40-man roster space to do so.
Today, it was announced that the Marlins were the team who wanted to take a chance on Tarpley's talent, sending the Yankees right-handed hitting third base prospect James Nelson and cash considerations to complete the transaction.
Tarpley was originally acquired by the Yankees from the Pirates back in 2016 as part of the late-season Ivan Nova trade. While he was a starter in the Pirates organization (all 20 of his appearances for the Pirates' High-A affiliate in 2016 were starts), the Yankees transitioned him to the bullpen for the 2017 season. However, he started the season on the injured list (due to shoulder soreness, which he revealed in an interview he gave with Pinstriped Prospects at the time) and didn't make his debut until June 10th. From that date on, he flourished, posting a 0.88 ERA in 41 innings pitched with only 18 hits allowed and a 42/18 K/BB ratio. While not as dominant in 2018, he still fashioned a 1.94 ERA in 69.2 IP with a 71/26 K/BB ratio. He was developing into a legitimate relief prospect and the Yankees summoned him for appearances in both 2018 and 2019. While in the majors, he has been able to keep up his ability to strike hitters out (29.4% strikeout percentage) but has not been able to limit the walks (13.1%) or the home runs (1.60 HR/9 IP). He has shown flashes of brilliance (he saved the Yankees' bacon on June 9th, 2019, against the Indians when he struck out the side in the 10th inning) but he never did seem to get comfortable in a big-league uniform with the Yankees. The Marlins will now give him an extended look.
As for Nelson, who was drafted in the 15th round in the 2016 draft, he was named the 2017 Marlins' Minor League Player of the Year, when he hit .309/.354/.456 in 102 games for the Marlins' Low-A affiliate in Greensboro. Those numbers are made more impressive when you consider he was only 19 years old (2.5 years younger than the average player in the league). This isn't to say his season was perfect, as he struck out 106 times in 432 plate appearances. As you may suspect, his BABIP was rather high (.399), which is what helped him reach the lofty triple-slash despite the high strikeout rate. In the most recent Fangraphs' blurb on the Marlins prospects, he received an honorable mention blurb under the "Thumpers" category, gaining praise for his athleticism but criticized for his crash since his 2017 campaign. That is fair, given that he hit .228/.279/.296 in 470 plate appearances for the Marlins' High-A affiliate in 2019. On a positive note, he did cut down his strikeout rate in 2019 (down to 18.9%) but he has shown little power and patience.
Nelson will be entering his age-22 season and I can see the Yankees potentially putting him in Trenton, given that he has played more than a full season now down in High-A. That said, his performance has been so poor that perhaps they will start him in Tampa to begin the season.
2080Baseball also wrote up a blurb on him after his 2018 season, which isn't entirely flattering.
If you want to read an interview from back in 2018 (when he was coming off his breakout season!), you can find one on Prospects1500. In the interview, he talked about how the Yankees were his favorite team growing up, so I bet he is excited to be traded to the team he grew up rooting for.
Bottom Line: When you DFA someone, your leverage is not high. The Yankees received a prospect back that they can at least work with to see if they can squeeze something out of him. As is, Nelson is minor league depth acquired for a pitcher with a big arm who has yet to harness it at the major league level. If the Yankees can do something with Nelson to get him back on a productive track, it will be a bonus.