Just over a year ago, the Mariners acquired Rob Whalen, along with Max Povse, in exchange for catching-prospect-turned-outfield-prospect-turned-catching-prospect, Alex Jackson. At the time of the deal, Fangraphs’ KATOH projection system pegged Whalen at 3.3 fWAR over the next six years.
Whalen, 23, struggled to stay healthy through his first spring training in the Mariners organization; a calf strain had him on crutches in mid-March, and he started the year on the disabled list with shoulder inflammation. He was eventually activated and optioned to Triple-A for the end of April, but the results suggest he wasn’t quite right. Having just come off an extended run of success in 2016 with the trials of Double-A, where he posted a 3.28 xFIP over 18 starts and actually stepped up his game after a promotion to Triple-A, he completely bombed upon revisiting the level in 2017, posting a 6.58 ERA that was inflated significantly by a major home run problem. Still, an xFIP hovering around 5.00 was a bit of a disappointment for someone Jerry championed all offseason long as a legitimate depth option for the major league rotation. After bouncing between Seattle, Tacoma, and Arkansas, Whalen found himself again on the disabled list in mid-June. Two weeks later, he was quietly placed on the restricted list for the remainder of the season.
One thing that’s worth keeping an eye on as Whalen turns the page to 2018 is that, according to Brooks Baseball (in an admittedly small sample size), Whalen threw 119 sinkers and exactly zero cutters in Major League appearances (including MLB Regular Season, Spring Training and Fall/Winter Ball) from 2014-2016 before apparently making the change to rely on what Brooks Baseball classified as a cutter, rather than his previously favored sinker to induce ground balls. It’ll be interesting to see if the trend continues into 2018 and beyond, or if he opts to return back to the more sinker-heavy approach that delivered better results throughout his time in Atlanta’s organization.
Reportedly, Jerry Dipoto mentioned at the Winter Meetings that Whalen is officially back into baseball and has been throwing with new bullpen coach, Brian DeLunas. He’s one year removed from a breakout 2016 in the upper minors, despite being much younger than league average (more than two years at Double-A and six years at Triple-A), so it’s not hard to find something to like.
If Whalen is going to get right in 2018 and earn a spot on the big league roster, the first step is going to have to be re-learning how to keep the ball in the ballpark. He moved from a pitcher-friendly environment in 2016 (he pitched over 100 innings for Double-A Mississippi whose home ballpark was far and away the most beneficial to pitchers) to pitch for Tacoma in the notoriously hitter-friendly PCL in 2017, where even the run-dampening environment of Cheney Stadium couldn’t help his FIP (5.60). His minor league home run rate—traditionally a strong point for the sinkerballer—reflected this change, and skyrocketed from 0.3 HR/9 to 1.5 HR/9. With these things in mind, I would advise you to set your expectations to “backend starter,” and anything more than that can be a pleasant surprise.