USATSI_18313756 — © Bill Streicher-USA TODAY Sports

Suárez Needs His Old Slider Back

Philadelphia Phillies starter Ranger Suárez has failed to live up to expectations so far, and diminished velocity on his slider is a major reason why.

Author:
Leo Morgenstern
May 26, 2022 3:00 PM EDT

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Philadelphia Phillies

Ranger Suárez had a magical breakout season in 2021, and no one could have expected him to repeat that performance. The Philadelphia Phillies were counting on him, however, to be a solid contributor in the 2022 starting rotation.

Unfortunately, Suárez has struggled out of the gate. Early on, his troubles could be attributed to visa issues that made him late for Spring Training. Now, seven weeks into the season, the 26-year-old starter’s problems can no longer be shrugged off.

The lone southpaw in the Phillies rotation has pitched a measly 7.1 innings in his last two starts, giving up six walks, 11 hits, and eight earned runs. He hasn’t looked good.

To his credit, Suárez has still been a serviceable fifth starter this year. His 4.74 ERA is not pretty by any stretch of the imagination, but it ranks 47 out of 65 National League starting pitchers (min. 30 IP). That’s all a fifth starter needs to do, and it’s a significant upgrade over what Matt Moore and Chase Anderson provided last season.

However, the Phillies are relying on Suárez to be more than just a capable fifth starter. With a below average bullpen and one of the worst defensive alignments in baseball, Philadelphia needs a top-of-the-line starting rotation in order to win games. A “serviceable fifth starter” isn’t going to cut it.

With his performance last season, it really seemed like Suárez could be a lot more than just a fifth starter. His 1.36 ERA was not going to be sustainable, nor was his miniscule home run rate, but even an ERA three times as high would be valuable from the back end of the rotation.

Heading into the 2022 season, FanGraphs Depth Charts projected pretty much exactly that: a 3.96 ERA for Suárez in 164 innings.

So, while Suárez has performed adequately this season, he has not been as good as expected, nor has he been as good as the Phillies need him to be. What gives?

The Results

Simply put, Suárez has not achieved the same results as he did last season.

For one thing, he has already allowed more home runs this year (6) than he did all of last season (4). It shouldn't really come as a surprise that his home run rate is higher this year; he allowed home runs on only 5.8% of his fly balls last season, which is nearly impossible to sustain long term.

That being the case, Suárez would be just fine if a higher home run rate was his only problem. Unfortunately, he's struggling in so many other ways.

Suárez is walking almost four batters per nine innings pitched, and his strikeout rate is significantly lower than it was last season. As a result, his strikeout to walk ratio is down to just 1.95. That’s 24% worse than league average. Last season, his K/BB ratio was 30% better than league average.

He is also allowing more hits and more extra-base hits than he was last year.

More walks and hits leads to more runners on base and fewer strikeouts means more balls put in play. Balls in play help to advance all those baserunners and ultimately lead to more runs scored. It’s not a good combination.

The Context

It would be easier to pin down the problem if Suárez was struggling in just one way, but he's having trouble in nearly every aspect of the game. He’s recording fewer strikeouts and allowing more hits, homers, walks, and runs.

Perhaps, then, a little more context might help.

Suárez is a left-handed pitcher, and, unsurprisingly, he has always performed better against left-handed batters. However, in 2021, he actually pitched quite well against righties.

He has continued to pitch very well against left-handers this season, but Suárez has failed put away right-handed batters like he did last year. In particular, his walk rate against righties (4.4 BB/9) is very high. No National League starting pitcher has walked more right-handed batters this year than Suárez.

He has also allowed 6 home runs to righties this year, tied for fourth-highest in the NL.

So, what was Suárez doing last season that helped him improve against righties, and why has that improvement seemingly disappeared?

The Stuff

One big change Suárez made in 2021 was using his slider far less often. He brought out the slider just 7.8% of the time last year, compared to 20.6% in 2019.

When he did throw the pitch, however, it was extremely effective.

Suárez threw 126 sliders last season, and opposing batters managed only two hits against the pitch all year. His sliders led to a 40.9% whiff rate. By nearly every metric available, his slider was the best pitch in his arsenal.

According to Baseball Savant, Suárez’s slider had the lowest hard hit rate and the highest swing-and-miss rate of all his pitches in 2021. It also had the lowest batting average, slugging percentage, and wOBA against, as well as the lowest expected batting average, slugging percentage, and wOBA against.

Unfortunately, Suárez seems to have lost the magic behind his slider in 2022. His slider whiff rate has gone down from 40.9% to 22.2%. The PutAway% on his slider (the percentage of two-strike pitches that led to a strikeout) has dropped from 23.1% to 9.1%.

The average exit velocity against his slider has gone up by more than 10 MPH, and the average launch angle has gone from 9 degrees to 25 degrees. Hitters are barreling up Suárez’s slider a ton this year, and it shows. The expected wOBA on his slider has gone up from .197 to .406.

Over the offseason, Suárez’s slider went from a dominant weapon to a liability. What changed?

The Answer

Thankfully, that big question has a very clear answer: velocity.

In 2021, Suárez averaged 84.3 MPH with his slider (per Baseball Savant). In his most dominant start of the season – his complete game shutout against the Pirates – he threw 17 sliders, 12 of which were faster than 85 MPH. His slider topped out at 88 MPH that day.

According to research from Driveline Baseball, which Eno Sarris wrote about for The Athletic, breaking balls thrown faster than 85 MPH are extremely effective. As John Creel, a pitching prospect in the Mariners system, puts it in Sarris’s article: “at 85? Almost anything plays.”

It really is as simple as that. In 2021, Suárez had a good slider because he had a fast slider.

In 2022, Suárez is averaging just 82.4 MPH on his slider (per Baseball Savant). That's a problem.

In his first start this year, the slider averaged 83 MPH. In his most recent outing, it was down to 82.3 MPH. Over his first 6 starts, Suárez threw only two sliders at 85 MPH or faster, one of which resulted in a hit-by-pitch.

Then, in his start against the Dodgers in LA, Suárez seemed to have finally regained the missing velocity. He threw his slider nearly 12% of the time and hit 85 MPH regularly. He averaged 84.5 MPH with the pitch.

As it turns out, his slider was not very effective that game – the Dodgers swung at just one of twelve – but the recovered velocity was a great sign. The only problem? It didn’t last.

Suárez seemed to lose faith in his slider after that night. He has thrown the pitch just ten times in his last two starts (5.8% of his pitches), averaging just 82.6 MPH and topping out at 83.6 MPH.

The Conclusion

The loss of his secret weapon slider has clearly been a huge problem for Suárez. All of his pitches have been less effective this season, but none more so than the slider, and the slider is the only pitch on which he has shown diminished velocity.

With one fewer weapon in his arsenal, it makes sense that all of Suárez’s pitches are suffering. He doesn't have an overpowering fastball — he succeeds by mixing pitches, and doing it well.

This could explain why Suárez has struggled so much against right-handers. It’s not that his slider is more effective against righties than lefties, but just that he doesn’t need to rely on a killer slider to punch out left-handed hitters.

Suárez has always been good when he has the platoon advantage, but he was able to succeed against righties in 2021 because he was masterfully mixing four above-average pitches (sinker, changeup, four-seam fastball, and slider).

Going forward, it looks like the best plan of action for Suárez is to increase the velocity on his slider. That's certainly easier said than done, but as he demonstrated in LA, Suárez still has what it takes to turn up the heat.