I hate to be the first one to say this, but somebody has to. The James Paxton trade is looking, uh, not great.
Nobody expected Justus Sheffield, Dom Thompson-Williams, and Erik Swanson to match Paxton’s production this season. All three of them are young, while Paxton was and is a borderline ace. What people did expect is for those players’ future production to come at all close to matching Paxton’s. That’s looking a whole lot less likely than at this time one year ago.
Justus Sheffield’s struggles were well-documented. The 23-year-old was abysmal in the Majors and in Tacoma, though he lit up Double-A Arkansas. The jury is still very much out on him, but he’ll need a solid year to stem the growing flood of naysayers.
Thompson-Williams, meanwhile, had a very tough go of it in Double-A last season. He saw his K% jump 6 points from his 2018 mark in high A, and he recorded an OBP of just .298. He has less top-prospect-shine than Sheffield, but 2020 also marks a critical year for his future development.
That leaves Swanson. At the risk of sounding like a broken record, Swanson struggled too. Nick Stillman wrote an excellent exit interview detailing Swanson’s struggles a few months ago, and I suggest you read it. He posted an MLB FIP of 5.96 last season, and he didn’t do much better in Tacoma, where he posted a 5.65 FIP. After some severe initial struggles (including an ERA of 11.85 the second time through the order!) the Mariners moved him to the bullpen, where it looks like he’ll stay for the foreseeable future.
At the annual media luncheon last week, general manager Jerry Dipoto seemed to tacitly confirm that Swanson isn’t being considered for a rotation spot anytime soon. He confirmed that Marco Gonzales, Yusei Kikuchi, Sheffield, and Kendall Graveman are virtual locks for the rotation: “Those are four you can just write down ... They will be in our rotation barring injury or the unexpected.”
For those being considered for the last slot, Dipoto seemed to name everyone except Swanson. He threw out names like Justin Dunn, Phillips Valdez, and even Logan Gilbert. And, of course, the team just yesterday announced the signing of Wei-Yin Chen.
Whether Swanson can turn it around and become a decent middle reliever depends on his ability to develop his secondary pitches. He primarily relies on his fastball, throwing it 68% of the time. He also has a slider and a changeup, each of which he threw approximately 15% of the time. With his fastball velocity sitting at just 93 MPH, he’s going to have to make the slider and the changeup into something.
Swanson did reasonably well as a reliever last season, posting an xFIP of 3.89 and a K% of 27.6%. However, as Nick rightly points out, these numbers were somewhat buoyed by a strand rate of nearly 90% and a BABIP against of just .211.
Encouragingly, Swanson made adjustments mid-season that seemed to lead to improvements. He adjusted his changeup’s release point in August to more closely match that of his fastball. After making that adjustment, his changeup’s groundball rate more than doubled, possibly hinting that that improved xFIP and K% might be sustainable.
At the moment, though, that sustainability is very much in doubt. Fangraphs’ 2020 ZiPS projections peg Swanson to post an FIP of 4.77 and an ERA+ of 84. Swanson will be given plenty of opportunity to prove himself on a 2020 Mariners team that looks to be going nowhere. At 26 years old, he still has time yet for development.
Like that of so many Mariner prospects before him, though, Swansons’ ceiling is lowering. After last year’s struggles, he’ll be fighting an uphill battle in 2020.