Sam Tuivailala has essentially split his time between Memphis and St. Louis so far this year. He has been “the extra arm” in the bullpen that gets sent down when a roster move needs to be made. Despite the consistent uncertainty, Tuivailala has put together a very nice year for the big league club. So nice, in fact, that his role should be increased. Matheny ought to give him the ball in high leverage situations.
All statistics through 8/23
Tuivailala has given up 2 earned runs since June 20th—a stretch spanning 15.1 strong innings. During this period his ERA has dropped from 3.00 to 2.15 (BaseballReference). But he’s more than just a “hot hand.” He’s made great strides in the last year. Gone are the days when Tuivailala would only throw his fastball and occasionally mix in a mediocre slider. He is becoming a multi-dimensional pitcher before our very eyes.
Still, Matheny refuses to use him in high leverage situations, giving him only 3.2 high leverage innings this year (before last night). As it stands now, Oh, Rosenthal, Bowman, and Cecil all far surpass Tuivailala in such innings (Fangraphs).
The 9th inning belonged to Trevor Rosenthal, until his recent move to the DL and news that he was done for the year as a result of TJ surgery. Recently (read: most of this year), Seung Hwan Oh has struggled, especially against lefties. So much so, that I would advocate for using him as a righty specialist (left-handed batters have a .355 average against him with a wOBA of .431, right-handed batters have a .205 average against him and a wOBA of .216 via Fangraphs). Nevertheless, Oh is still widely viewed as a late-inning reliever, even in the latest Fangraphs Bullpen Report. Oh’s lack of success in this role leaves a hole that should be filled by Tuivailala.
As I said above, Tuivailala is developing into a multi-dimensional pitcher, no longer relying as heavily on his fastball. Here is a look at how his repertoire has changed from 2016 to 2017.
Sam Tuivailala pitch frequency (2016-2017)
His fastball frequency has dropped 10 points in the last year. As more and more MLB hitters sit on the fastball, this is a good development. This decrease didn’t result from a lack of trust in the pitch. He throws it at the same speed (96+) as he did in 2016. And the vertical movement has actually increased to 8.90 inches (Remember: vertical movement means the ball drops 8.90 fewer inches than a spinless ball).
Last week I wrote about Michael Wacha’s tremendous fastball, resulting from a spin rate of 2160 rpm that causes the ball to “rise.” Tuivailala has an average fastball spin rate of 2310, giving the appearance of an even larger “rising” effect than Wacha’s fastball. But for Tuivailala, it’s not just about rise, it’s also about location.
He has shown an ability to locate pitches on the outer portions of the strike zone.
Almost one-fourth of all fastballs thrown by Tuivailala are on the edge of the zone, an improvement from his numbers last year (BaseballSavant).
With a rising fastball at 96+ miles per hour that he can locate on the edges, Tuivailala has a great primary pitch to rely on. But there’s more.
This year, he has been able to use his fastball to set-up his off-speed pitches. Tuivailala’s curve has averaged 8.21 inches of positive horizontal movement (for a right-handed hurler, that is glove-side movement). The same pitch also drops about 5 inches by the time it reaches the plate (BrooksBaseball). If located properly and paired with the right sequence of pitches, it devastates hitters.
Examine this at-bat against Jose Reyes (BrooksBaseball AtBat). Tuivailala started with a curveball that had 9 inches (!) of horizontal movement for strike one. Then he threw an outside fastball. After throwing another fastball that was fouled back, he threw a 98mph fastball away to set-up a low and in curveball:
It was a beautifully thrown pitch to top off a well executed at-bat. The fastball-curve combination proved to be too much for Reyes to as he came out of his shoes and had to take a few quick steps back to regain his balance.
Tuivailala has increased his curveball usage, but has decreased his slider frequency. It seemed he had lost trust in his slider last year, which probably wasn’t far from the truth as hitters had a .400 average against it in 2016. But this year, opposing hitters are batting just .095 against the pitch—a remarkable number in its own right and a drastic improvement from 2016 (BrooksBaseball).
But the movement of the slider hasn’t changed much in the last year. The key for this pitch has been location. Take a look at the heat map for Tuivailala’s slider in 2017.
It’s clear why opponents have a .095 average against the slider—that location is unhittable. Whether it’s low and away to right-handed hitters or low and in to left-handed hitters, it’s a near impossible pitch to do something with from a batter’s perspective.
As a result the slider has become not a complementary pitch for Tuivailala, but an out pitch—its whiff rate has tripled from 2016 to 2017 and lefties have yet to record a hit off it (BrooksBaseball).
It’s worth commenting that analyzing a reliever’s performance within a given year is done with the caveat of having a small sample size. Regardless, patterns and improvements in different areas are still visible. Tuivailala is no exception to this rule (even considering his appearance last night). He has improved his ability to locate his fastball on the edges of the strike zone, he has been successful in pairing the aforementioned fastball with his curveball, and he has started to pick his spots with his slider to overwhelming success.
Now, without Rosenthal, it’s time that Mike Matheny use him in more high leverage situations as a back of the bullpen reliever—Tuivailala has earned it.