James Paxton trade: MLB prospect expert weighs in on Justus Sheffield and rest of Mariners' return

The Seattle Mariners and New York Yankees made a blockbuster trade on Monday night. The Mariners sent ace James Paxton to New York in exchange for three prospects: lefty Justus Sheffield, outfielder Dom Thompson-Williams, and righty Erik Swanson.

To make sense of the trade, we asked former Baseball Prospectus minor league editor Craig Goldstein to break down the involved prospects for us. You can follow Craig on Twitter (@cdgoldstein).

Do you think the Mariners received a fair package for Paxton?

I think it's fair, but only just. Paxton is a dynamic pitcher who slots at the top of the rotation when healthy, but who is consistently not healthy, and has two years remaining until free agency. Sheffield is an electric arm who can touch 96 with sink and has two secondaries both of which flash plus (slider, change). The problem is that despite his athleticism, he often lacks command and will occasionally lack control. That, plus his shorter stature and no track record of logging a full spate of starter's innings lead to a lot of questions about whether he is a starter in the long term.

I think that he can be, especially since we're asking less and less of starters these days, but that still calls into questions the ultimate value received. Maybe he ends up as a Miller/Hader-esque multi-inning reliever, and that's not a bad result! But is it worth two years of a bonafide, if oft-missing ace?

Can Sheffield eventually replace Paxton at the top of Seattle's rotation?

He has the talent to be a No. 2 starter if it all clicks. That's in the range of Paxton's output given the time he's missed over the years, but the more conservative school of thought would plant him in the middle of the rotation. Six years of that compared to two of Paxton isn't a bad tradeoff, but it's also hard to build a true winner out of those types of tradeoffs in the long-term (though we've seen mild rotations take it all home, i.e. Kansas City's run).

What's the book on Thompson-Williams?

Shot to be a fourth outfield type, with a likelihood of an up-and-down guy if he can hit. Has athleticism to go get it in the outfield, but is still raw at the plate with a bunch of swing-and-miss that is likely to get exploited in the upper levels of the minors, where pitchers will make fewer mistakes that he can take advantage of while busting him inside on the hands. Not a bad depth piece to have available, but probably more of a fourth piece in these types of swaps than a third.

What about Swanson?

Potential back-end starter. Will sit in the low-to-mid 90s with his fastball, and touch higher on a good day. He'll throw a slider and a curve, along with his changeup, giving him the arsenal to turn a lineup over multiple times. He's got a frame to log innings, but ultimately the stuff might play better, and the inconsistencies might be less apparent, if he pitches out of the bullpen. Swanson is another possibility to be a multi-inning reliever thanks to the multitude of pitches available to him. He's an intriguing guy but I think fairly tame as a second piece for an arm that provides as much impact as Paxton.

Where do these three rank within the Mariners system?

Deceptively high? My previous comp for Seattle's system was Janet from The Good Place's void. Sheffield is the best prospect in the system now, and it's not particularly close. Swanson is in the top ten, and probably comfortably so. Thompson-Williams might have a case for back end of the top ten, but that says more about the state of the Mariners system than it does about Thompson-Williams. He shouldn't really be close to one of these lists in any normal organization.

Do the Yankees still have the pieces to make another big trade?

Yep. Sheffield was their top prospect heading into the offseason, but they still have guys like Estevan Florial, Everson Pereira, Chance Adams, Jonathan Loaisiga, Roansy Contreras, Luis Gil, Antonio Cabello, etc. etc. Those might not all be household names, but they all carry value and are of interest around the league.

CBS Sports Staff

R.J. Anderson joined CBS Sports in 2016. He previously wrote for Baseball Prospectus, where he contributed to five of the New York Times bestselling annuals. His work has also appeared in Newsweek and... Full Bio

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