Are the Phillies’ Starters Holding Back?

The Philadelphia Phillies have one of the best starting rotations in baseball. That’s not exactly news, or at least it shouldn’t be.

The Phillies lead NL teams in starting pitcher WAR (per FanGraphs) this season. They also led the Senior Circuit in 2023. And 2022. They finished third in 2021 and second in 2020.

Philadelphia’s success has a lot to do with the two mainstays at the top of the rotation. Zack Wheeler is an ace among aces. Aaron Nola is the most durable pitcher in baseball. Those two have combined to make 215 starts over the last five years, averaging more than 6.0 IP per outing and more than 5.0 fWAR per 30 starts.

However, the Phillies have also become an unheralded mid-rotation pitching factory under the watchful eye of coach Caleb Cotham. Ranger Suárez has blossomed into a strong No. 3 starter. Cristopher Sánchez is on the same trajectory. Moreover, Matt Strahm turned out to be a terrific stopgap last year, and Spencer Turnbull is off to a similar start in 2024.

Through 13 games this season, Phillies starters rank third in the NL in innings pitched, second in strikeout-to-walk ratio, and first in ERA. They also rank second in FIP, first in xFIP, and first in SIERA.

The pitch modeling systems are equally high on Philadelphia’s starting five. They rank second in Pitching+ (Stuff+) and botERA (PitchingBot).

However, there is one statistical category in which the Phillies have tumbled down the rankings: velocity. Their starters are averaging 92.3 mph on their four-seam fastballs this season. Only two NL clubs are throwing slower. Philadelphia ranks low in every other pitch type, too:

From all appearances, this isn’t affecting the rotation’s overall performance. The results speak for themselves.

Still, it’s curious. The Phillies love velocity. The back end of the bullpen features arms like José Alvarado, Gregory Soto, Seranthony Domínguez, and Jeff Hoffman. The team aggressively promoted Orion Kerkering last year after his velocity shot up. Philadelphia has had one of the hardest-throwing bullpens in baseball over the past three seasons.

Furthermore, it’s not as if the rotation transformed over the offseason. The Phillies are using four of the same starting pitchers they deployed down the stretch in 2023. The only change is that Turnbull has temporarily taken Taijuan Walker’s turn.

Walker is hardly known for his blistering velocity. In fact, he and Turnbull averaged the exact same velo on their four-seam fastballs last season (92.9 mph).

It’s not as if velocity is down around the league, either. The average four-seam velocity for a starting pitcher in 2024 is 93.7 mph. Last April, the league-wide average four-seam was 93.5 mph. The year before it was 93.4 mph. The rest of the league is throwing ever-so-slightly faster, but the Phillies are falling off the pace.

This chart shows the average velocity of each Phillies starter’s primary fastball (1) so far this year, (2) all of last year, and (3) during his first three starts of last year. It also shows his maximum velocity in each time period:

Four of the Phillies’ five starters are throwing noticeably slower this year. The only one throwing faster is Sánchez, who is entering his first full season with a guaranteed job in the rotation.

All four of Wheeler, Nola, Suárez, and Turnbull are averaging career-low velocities on their primary fastballs. None has had a single start this year in which his average fastball velocity was as high as his average in 2023. On top of that, none has come close to matching his maximum velocity from last season.

Were it just one player, I might be worried about an injury. Yet, instead of a problem, this seems like a pattern. It’s too early to draw any serious conclusions, but this is a trend worth watching.

Are the Phillies instructing their starters to throw with less power this season? Or, perhaps, is the team asking them to ramp up throughout the year instead of giving it their all straight out of the gate? I wouldn’t be shocked.

The Phillies are heavily reliant on their starting rotation. Their offense is good. The back end of their bullpen is nasty. Still, it’s the rotation that will get them to the postseason, and it’s the rotation that must lead the way once they get there.

A major injury could deflate this team’s postseason hopes faster than a pin to a balloon.

By holding back, at least in April, perhaps the Phillies starters are trying to keep that pin as far away from the party decorations as possible.

Far too many starting pitchers around the league have suffered devastating elbow injuries this year alone. There has been plenty of talk about the pitch clock, the sweeper, and rising spin rates causing an uptick in injuries, but high velocity still seems to be the primary culprit.

If starting pitchers can continue to thrive without throwing at max velocity, then maybe that’s exactly what they need to do.

Wheeler, Turnbull, and Suárez are certainly thriving. They have displayed sterling control, maintaining high strikeout rates and exceptional walk rates. Wheeler has added a nasty splitter to his already deep arsenal. Turnbull is leaning on his new sweeper. Suárez is actually throwing his sinker more than ever, but several of his secondaries look stronger this year.

The only Phillies starter struggling so far this season is Nola. His fastballs have been ineffective out pitches, and batters aren’t whiffing on his offspeed stuff like usual. He hasn’t introduced anything new to his arsenal to compensate for reduced velocity, and the movement profiles of his pitches are less unique at lower speeds.

Nobody can blame Nola for his velocity and control in his latest start. He pitched through poor weather and said he deliberately held back from throwing his hardest. However, that doesn’t explain his first two starts; his velocity was still down compared to last year. His maximum velocity is also notably lower than it was at this time last season.

On the bright side, Nola often takes some time to ramp up to his maximum velocity. These charts show his rolling 10-game velocity from 2021-23:

Whatever the Phillies are up to, they’re smart enough not to take a blanket approach with all their pitchers. Sánchez doesn’t seem to be taking it easy, and hopefully, Nola will increase his velocity in the coming weeks.

As for the rest of the staff? We’ll just have to wait and see what’s in store. If nothing else, fast or slow, the Phillies rotation has earned the benefit of the doubt.

We’ve seen Wheeler, Suárez, and even Turnbull look dominant when they throw their hardest, but max-effort pitching isn’t the only way to succeed.

Just ask the tortoise and the hare.