Breaking Down Phil Maton’s Hot Start

Last season, Phil Maton watched from the bench as the rest of the bullpen combined to throw a sub-1.00 ERA – First in postseason history – en route to the team’s World Series victory. He would miss the postseason run with a broken bone in his hand after punching a locker following the final regular season game. Even if healthy, Maton was no lock for a postseason bullpen spot. Now a month through the 2023 season, he looks like the best reliever in baseball.

In 11 2/3 innings the 30-year-old has given up just two hits and a walk while striking out 13 of his 40 batters faced. He ranks first in WHIP (0.257) and sixth in expected slugging (0.203) and expected ERA (1.57). He has become a key piece for an Astros bullpen that ranks fifth in K/9 (10.38) and ERA (2.96).

There are three reasons Maton turned from postseason reject to crown jewel of the pen: a new pitch mix, the league’s most devastating curveball, and a lack of line drives. All of this has transformed the righty into yet another arm for Houston.  

Pitch Mix

League-wide fastball usage is down and Maton is no stranger, dropping his four-seamer usage by 15 percentage points. He has followed the modern trend of pitching backwards – using off-speed pitches to set up the fastball (or more off-speed pitches) – like Dylan Cease, Shohei Ohtani, and Joe Musgrove.

Instead, the relief man has turned to the curveball as his go-to pitch, while also throwing more sweepers. Also noteworthy, in the age of turbo sinkers and 105-MPH fastballs, Maton has experienced his jump without a single pitch averaging 90 MPH.

It comes as no surprise that Maton turned to the curve given that hitters batted just .165 against it in 2022. He had always been elite at producing weak contact – 97^th percentile for average exit velocity and 98^th in hard-hit percentage in 2022 – now his expected statistics are starting to match up. After ranking near the middle of the pack a year ago, the righty is now positioned in the 97^th percentile or better in expected batting average, slugging, and wOBA.

Trouble With the Curve

Following the 2022 season, Maton set out to add more drop to his curveball. When spring arrived, the curveball had an additional 120 RPM – fifth amongst curveballs (3119 RPM) – and 3.5 more inches of drop. The added vertical movement took it from 51^st-most in 2022 to 17^th this season. Coupled with the most horizontal movement (19.4) – second to himself since 2015 – baseball’s most valuable pitch was born.

With any event that occurs, a run expectancy difference is calculated, and we call that run value. Maton’s curveball has a -5 RV – second behind Charlie Morton (-7) – placing it amongst the game’s elite curves. However, per 100 pitches, Maton’s curveball (-8.9 RV/100) is the best of any pitch from all pitchers.

Opponents have yet to record a hit off the curveball, generating whiffs 37.5% of the time. The dominant go-to pitch has paved the way for his sweeper to emerge. The tertiary pitch is causing batters to whiff 44% – an 11-point increase from a year ago – while having zero expected statistics over .070 against it.

Lack of Liners

Both Maton’s groundball and flyball rates are the highest of his career with a subsequential career-low line drive percentage (4.2). This is a terrific development given line drives produce the highest runs per out (1.26). The righty has thrown in the strike zone 52.9 percent – highest since 2017 – as well as hunting strikes early. An absurd 70% of plate appearances against Maton result in a first-pitch strike.

Opposing hitters are getting on top of Maton’s pitches (45.8%) like teammate Framber Valdez (46%). With more pitches in the zone, the right has relied on the late break – 95^th percentile – of his arsenal to generate whiffs and weak contact. In addition, the more aggressive approach has resulted in a career-low walk percentage (2.5%). The lack of line drives has significantly reduced expected statistics against Maton as opponents have struggled to hit anything cleanly.

To wrap it up, Maton’s Baseball Savant percentile rankings look more like your high school valedictorian’s report card than an MLB pitcher after a month. His reworked curveball and philosophy have transformed him into someone who won’t be left off any more postseason rosters.

Statistics up to date through April 27