As the 2018 trade deadline approached in late July, the Mariners were plummeting out of contention. Most fans and writers believed that if the team was to have a chance to stop the bleeding and salvage a playoff spot, they would have to make a splash at the deadline. Unfortunately, it appeared that the team’s “splash” had come in late May with the trade for Denard Span and Álex Colomé.
The team’s deadline acquisitions ended up coming in the form of a paltry trio of relievers and Cameron Maybin. Perhaps predictably, the moves weren’t followed with an appreciable uptick in performance, and the Mariners were left with little to show for their trouble. As it turns out, that “little” is now just right-handed reliever Sam Tuivailala.
Unlike the other deadline acquisitions, Tuivailala is under team control through 2023 and still has an additional year until he’s arbitration-eligible. At just 26, he seems like a prime candidate to play a part in the Mariners purported window of contention of 2020 and 2021, if he can produce. So, does that seem at all likely?
Unfortunately, that question is complicated by the ruptured Achilles tendon that ended Tuivailala’s 2018 season. Achilles injuries are tricky. Zach Britton was sidelined for a good portion of 2018 with a torn Achilles, and though he was able to return before too long, he wasn’t the dominant reliever that he’d been previously until late in the season. Britton’s injury was to his landing leg, however, while Tuivailala’s was to his push-off leg. Beyond that, there’s no telling how any particular leg will respond to an injury. It’s anybody’s guess how Tuivailala’s 2019 will go, even after he returns in July-ish.
Let’s assume, though, that Tuivailala is able to eventually return to full strength. What can we expect from him?
Sam Tuivailala’s 2017 vs. 2018
As you can see, though Tuivailala’s FIP remained pretty stable between 2017 and 2018, his peripherals took a sizable hit. He struck people out less often, he walked more people, he got hit harder, and he wasn’t able to induce soft contact as often. So what changed?
Tui’s fastball and curveball were pretty much the same between 2017 and 2018. His slider was... not. Its velocity increased by nearly 2.0 MPH, which is a lot when the relative speed between your primary and secondary pitches is your main means of keeping hitters off-balance. The spin rate on the slider also decreased by nearly 50 RPM. That isn’t a huge change, but it also isn’t insignificant.
While it’s not obvious what Tui might have done to cause this change, or whether reversing it might be feasible, it is encouraging that his struggles seem to be rooted in a tangible cause. It might not just be the change to his slider, but I don’t believe that it’s a coincidence that the Pitch Value of his slider on Fangraphs tumbled from 4.7 wSL/C to 0.5 wSL/C between 2017 and 2018.
Unfortunately, it’s not clear when Tui will be able to return to a fully regimented pitching routine, which is when he would best be able to implement any changes. We might not be able to see what Tuivailala is actually able to do until the end of 2019, or even Spring Training of 2020.
One thing’s for sure, though: Tuivailala is just about the most supportive teammate you could ask for.
He can't play anymore this season but Sam is out here trying his darndest anyway pic.twitter.com/IRZpDx6geZ— tee (@TeeMil24) August 15, 2018
The fans will all be rooting for Tui, the first player of Tongan descent in MLB, to come back strong in 2019 and figure it all out. You can be sure that Tui will rooting just as hard for the rest of the team.