I have a confession to make. I love writing about relievers. In my short tenure here, I’ve written about them quite a lot. I wrote about John Brebbia, Matt Bowman, Bud Norris, and Jordan Hicks. One of the first Fan Posts I wrote here was about bullpen construction. It’s a well I’ve gone back to quite a lot, and I imagine that trend will continue. It’s not just me, either. Think about how many columns have been written about savior-turned-pumpkin-turned-okay Greg Holland, or about any of the various star-crossed offseason acquisitions the Cardinals made this year. It makes total sense, too. Writing about relievers is the best. With sample sizes as small as a reliever’s half-season, there’s nothing like stabilization there. As a writer, as an analyst, you can peer into the depths of pitch type and pitch usage for meaning. Results? Who cares! Check out the rise on this guy’s fastball, though. Most relievers have something outstanding about them, and they’re always changing. Try writing something like that about a solid third or fourth starter.
Online baseball writers probably focus more on relievers than they should, if they want to focus on what affects the game most. There’s a happy double coincidence of needs here, though. Fans care about relievers a ton too, possibly even more than writers. I might have two months of experience to draw on as a writer, but I have years and years of being a fan under my belt. I absolutely love articles about what a random reliever has done to become unhittable, or what a great reliever has done to become terrible. Every time a Cardinal reliever blows a save or strikes out the side, I need to know what’s going on. Tommy Kahnle? I’m into it. Whatever in the world happened to Seung-Hwan Oh? Captivating reading. So here’s the deal. I’m writing about Sam Tuivailala today. He did some things. With his pitches. Hopefully, you’ll read it- even more hopefully, you’ll like it. In a month or two, though, we’ll probably be back here, and I’ll be telling you about how Austin Gomber is the heir to Andrew Miller, or about the decline and fall of the house of Bud Norris, or whatever other random thing a Cardinals reliever has gotten up to.
Back to the topic at hand- Tuivailala. A quick look at the Cardinals bullpen to start the season would show you that his position on the team was precarious. Four new relievers were coming into the fold. Brett Cecil, Matt Bowman, and apple of Yadi’s eye Jordan Hicks were likely to stick with the big-league team. That’s seven men, and the eighth spot would probably rotate a little bit. The problem, though, is that Tuivailala didn’t have any options left. He’d have to be exposed to waivers to go down to the minor leagues, and surely someone would claim him. He wasn’t exactly lights out, either. He’d somehow made it through his option years while accruing exactly 0 fWAR (and .7 bWAR, for comparison’s sake). In my head he’d always been a wild power pitcher with a shot at gaining command, but that view had slowly been fading, replaced by a vision of a competent but unexciting middle reliever. When the season started, things looked worse. Tui went out throwing 4 ticks slower than last year. That’s alarming. He went on the DL right away, unsurprisingly. I’d already mentally moved on.
A funny thing happened next though. When Tui came off the DL, he was back to his previous velocity. The strikeouts came back. If you didn’t look too hard, it looked like he was back to his same old self, a decent bullpen arm with a nice slider and no options. Under the hood, though, a lot of things changed. If you look at Sam Tuivailala from 2015 and 2018, they seem to be two totally different pitchers. The changes seemed subtle at first, but they’ve built over time, and I think they’ve made him into a much better pitcher than the average Cardinals fan probably thinks. Let’s break those changes down.
First things first- if you asked me what pitches Tui threw, I’d say he used a four-seam and a slider as his two pitches, and maybe sprinkled in other things once in a while. In 2015 and 2016, I would have been right. He used those two pitches more than 90% of the time each year. In 2017, he added a two-seam fastball and a curve, but was still primarily a fastball-slider pitcher. This year, he’s become a renaissance man:
What started out as a subtle shift has become anything but. Tuivailala is throwing everything with equal frequency. It’s not very easy to find a reliever who throws two breaking balls this frequently. You’ve got David Robertson and Dellin Betances. You’ve also got whatever a Daniel Coulombe is. So there’s your dominant reliever upside, and there’s your forgettable downside. Clearly, we need more information.
There’s one other subtle shift in pitch mix, as well. In addition to evening out the total frequency, he’s made himself considerably less predictable on the first pitch of at-bats. Before this year, he had thrown over 70% fastballs to both lefties and righties to open at-bats. So long as he was even or behind, he’d stick with a heavy diet of fastballs. As soon as he got ahead, however, this percentage dipped down into the 40’s as he went to his two breaking balls. This is pitching by the book, and it’s also maybe the most predictable thing you can face as a hitter. This year has been a total reversal of trend. He’s thrown first-pitch fastballs to lefties 58% of the time and righties only 49% of the time. When he gets ahead, those percentages barely change- 54% to lefties and 52% to righties. In other words, good luck getting inside Tuivailala’s head as a batter. He throws whatever he wants, whenever he wants to.
Of course, throwing a diverse group of pitches can’t help you much if batters are picking them up right out of your hand. Here we find another point of improvement for Tuivailala. Historically, he’s thrown his fastball from a high release point, higher than three-quarters. His breaking pitches started a little bit lower. It was never anything huge, but there was always a gap there. This year, he’s eliminated that gap by dropping his arm slot on his fastballs a bit and leaving everything else the same. Don’t take my word for it, though. Here are his release locations from 2017:
He’s down to a single pitch released above 6 feet off the ground this year, after around 20% of his pitches last year started from that high. This is a small advantage, but the small advantages add up. Before this year, you could figure out what Tui was going to throw based on the count, and then confirm it based on where he released the ball. This year- you might as well roll some dice. You’re not getting anything from him.
Last but not least, Tuivailala’s new pitch locations continue the trend of bucking conventional wisdom about baseball. You basically know the deal. Fastballs are in the strike zone to get strikes, and off-speed pitches hit the dirt to get whiffs. Maybe fastballs creep upstairs sometimes, but there’s a pretty set order of things. Not so with Tui. As mentioned above, his breaking ball usage is up this year. He’s also throwing a lower percentage of pitches in the strike zone than last year or the year before. This makes sense at first blush- more breaking balls in the dirt, fewer pitches in the strike zone. There’s just one problem with that convenient explanation. He’s thrown breaking balls for strikes more often than fastballs! On the year, 53% of his breaking balls have been in the strike zone (as defined by Baseball Savant). Only 45% of his fastballs have done the same. He’s been aiming for corners more with his fastball, and dropping in more sliders and curves for strikes. He’s a sphinx out there, in other words.
So, here’s the weird thing about all of this. The new and improved Tuivailala is a modern analyst’s dream. He bucks everything that hitters know about hitting. He mixes pitches like a Cuisinart. He disguises his release point exceptionally well. He can throw any of his pitches for a strike or to get a swing and a miss. He hasn’t really been all that good, though. It’s a small sample size, no doubt, but since coming back from injury he has recorded a 3.44 ERA and 3.54 FIP over 18 ⅓ innings. He’s struck out 22% of the batters he’s faced while walking 6%. It’s really hard to see a change, even if it feels like there’s been one. That, in a nutshell, is the trade-off when you talk about relievers. I look at Sam Tuivailala and see a magnificent reinvention of his game. He’s doing things differently, and in all the ways I love. He’s also done it for exactly 80 batters faced. We’re so far into small-sample territory we couldn’t see statistical significance with a telescope. So I’m staking a claim today. Sam Tuivailala is going to be good the rest of the year, and he’s actually already really good. We just don’t know it yet.