From Reliever to Relief: How Ranger Suárez Gave the Phillies a Rotation Boost

The Phillies’ rotation hasn’t been a total disaster this season. Zack Wheeler is a top Cy Young candidate, and Aaron Nola has held his own as one of the league’s best starters, with the two combining for 10.8 WAR. But the rest? Zach Eflin went down in mid-July with a knee injury before getting surgery earlier this month. Vince Velasquez spent nearly two months on the injured list with a blister and was recently DFA’d; he now wears a Padres uniform. Spencer Howard had his own sophomore struggles before being traded to the Rangers at the deadline. Enter 26-year-old left-hander Ranger Suárez, who, after picking up the slack in the bullpen and briefly filling in as the team’s closer, was called upon to step into the rotation.

Suárez has been remarkably consistent since being stretched out as a starter, going at least five innings and allowing two earned runs or fewer in each of his last six starts:

Ranger Suárez Last Six Starts
Date Opp IP H ER HR BB SO
2021-09-20 BAL 6 7 2 0 1 5
2021-09-15 CHC 6 6 2 1 1 8
2021-09-09 COL 6 5 1 0 1 6
2021-09-04 @MIA 5 2 0 0 2 7
2021-08-29 ARI 5.1 5 1 0 2 5
2021-08-24 TBR 6.2 6 1 0 1 7

During that stretch, he has only given up one home run. He’s been prolific in that regard all season, having allowed just four homers total and boasting a minuscule 0.26 HR/9 rate over those last six starts. If we extend that to the beginning of August, when he first took the mound as a starter, that becomes an even more impressive 0.18 HR/9 over 49.2 innings pitched. Not only does he seem to have the home run thing figured out, but he also doesn’t give out many free passes either: He’s issued no more than two walks in each of his last six games, good for a 5.6 BB%.

That’s all despite the fact that, per Baseball Savant, Suárez’s fastball has an average spin rate of 1,937 rpm, which puts him in the second percentile league-wide. That’s right: his fastball has basically the lowest spin rate in the majors. But while high spin rate has been all the rage of late, an extremely low spin rate can be a weapon, too. As a reminder, more fastball spin gives the ball “ride,” meaning that it creates the illusion to the batter that it is rising as it approaches the plate; the reason that high spin is so celebrated is that these fastballs tend to create a lot more whiffs. Conversely, a low-spin fastball will drop more as it approaches the plate.

Suárez is a sinker-baller at heart: He relies on it more than any other pitch, throwing it 45.6% of the time, with a healthy dose of four-seamers and changeups to go along with it. (He also occasionally sprinkles in some sliders, which I will get to later.) The purpose of a sinker is to get it to drop to make it difficult for hitters to get their barrel underneath the ball and put it in the air, and few pitchers are doing that better than Suárez right now. His sinker is second to only Adrian Houser’s in Baseball Savant’s Run Value metric, and its .247 xwOBA against is beat only by Wheeler among all pitchers with at least 100 plate appearances ending with that pitch.

The movement of the sinker is key for Suárez. Thanks to the sub-2,000 rpm spin on the pitch (it averages 1,846), he gets 2.2 more inches of drop on the pitch compared to the average sinker. What this translates to is a lot of grounders. Unsurprisingly, Suárez is a ground-ball machine, with a 58.9% rate, good for seventh among pitchers with at least 80 innings pitched this season. But he gets weak contact on balls in the air as well. Like many pitchers who pair a sinker with a four-seam fastball, he tends to use the former down in the zone and throws the latter higher, as well as out of it:

The chart above shows how he locates the two pitches differently, with the four-seamer in red covering the top half of the zone and inside part of the plate for righties and the sinker in orange all over the lower portion of the zone and the outer part of the plate for righties. Utilizing his command of these pitches coupled with the movement he creates has made life difficult for hitters; they’re barreling the ball at a rate of just 3% (98th percentile) to go along with a 31.4% hard-hit rate (92nd percentile). Hitters aren’t just hitting weak ground balls against Suárez; they’re also hitting weak fly balls, culminating in a line-drive rate of 16%, sixth lowest among pitchers with at least 80 innings pitched. Compared to fellow sinker-ballers, he is allowing the weakest contact on fly balls by far, resulting in a 6.9 HR/FB%:

Sinker Dominant SP Batted Ball Rates
Name Team SI% GB/FB LD% GB% FB% HR/FB
Framber Valdez HOU 51.9% 4.75 15.1% 70.1% 14.8% 19.6%
Ranger Suarez PHI 45.6% 2.34 16.0% 58.9% 25.1% 6.9%
Adrian Houser MIL 53.9% 2.70 19.2% 58.9% 21.8% 14.5%
José Ureña DET 48.5% 1.89 20.4% 52.0% 27.6% 14.6%
Joe Ross WSN 47.2% 1.19 20.5% 43.2% 36.3% 15.5%
Dane Dunning TEX 53.6% 2.07 20.5% 53.6% 25.9% 13.4%
Alex Wood SFG 46.4% 1.84 21.0% 51.1% 27.9% 14.4%
Steven Matz TOR 52.4% 1.39 21.0% 45.9% 33.1% 12.1%
Brett Anderson MIL 45.8% 3.13 21.5% 59.5% 19.0% 16.7%
Brady Singer KCR 57.6% 1.79 21.8% 50.1% 28.1% 13.0%
Sean Manaea OAK 60.1% 1.21 22.9% 42.3% 34.8% 14.6%
Zach Davies CHC 52.1% 1.29 24.8% 42.4% 32.8% 16.3%
Minimum 80 innings pitched

Let’s stay on pitch mix for just a bit longer. For the better part of this season, Suárez had seemingly dropped his slider from his arsenal entirely, throwing it just 6% of the time compared to a 19.8% usage rate from 2018 through ’20. In a relief role, it’s not uncommon for pitchers to rely on a single secondary pitch, but it’s tough to be an effective starter without a more versatile arsenal. But as noted by Scott Lauber of the Philadelphia Inquirer, Suárez seems to have gained newfound confidence in the slider. During a start on August 29 against Arizona, he threw it 13.7% of the time and with great success, generating four whiffs:

Since that start (game 33 when referencing the x-axis in the graphic above), he’s had two more turns (September 4 against the Marlins and earlier this week against the Orioles) where he’s thrown the pitch at a similar frequency. The re-introduction of his slider has not had a huge impact on Suárez’s results — his contact rates allowed and quality of contact have remained steadily excellent — and it grades out similarly to his changeup according to Statcast, each with a -1.1 RV/100 value. But in the starts that he’s used the slider more freely, it’s been mostly in favor of the changeup, and while his stat line doesn’t show any big change or improvement, the pitch is something of a necessity, as hitters are now seeing him multiple times in a game. It also offers different movement from his other pitches and elicits swings and misses from opposing hitters at a rate greater than the changeup.

If the Phillies do win the East, it’ll be due in part to Suárez, who has taken on high-leverage situations in the back of the bullpen and added a stabilizing arm to the rotation behind Wheeler and Nola. But at the same time, he’s slightly overperformed his expected stats (a 2.92 FIP compared to a 3.48 xFIP); whether he can remain among baseball’s elite in limiting quality of contact is an open question. Even though he’s having some success with increased slider usage, he’s wisely stuck to his primary sinker/four-seamer combo which continues to work well. If he can successfully round out his secondary offerings, he may start missing enough bats that some regression in contact quality won’t matter very much.





Chet is a contributor for FanGraphs. Prior to FanGraphs, he wrote for Purple Row. When not writing about baseball, he is a data scientist and outdoor sport enthusiast. He can be found on Twitter at @cgutwein.

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SenorGato
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SenorGato

Love the emergence of a true sleeper, outstanding MiL pitcher

Sucks he had TJ but otherwise I’m a believer