The NL West has become one of the most competitive divisions in MLB, with the Diamondbacks reaching the World Series in 2023 and the Dodgers finishing with 100 wins. There was plenty of quality on the pitching side of things, as the Dodgers, Padres, and Giants all finished the year with a team ERA+ over 105.
Despite this, a few veteran pitchers underperformed, with younger arms such as Bobby Miller and Kyle Harrison gaining more recognition for their arrivals in the big leagues. While age is not on their side, these veteran arms can bounce back in 2024 with a few adjustments and reestablish themselves as above-average pitchers.
Yu Darvish
Yu Darvish, about as complex of a pitcher as they come, posted career-worst full-season numbers in 2023 with a 4.56 ERA and 4.03 FIP in 136.1 innings. The year before, though, Darvish proved he was still an elite pitcher at 36, posting a 3.10 ERA and 3.31 FIP, earning himself a 6-year, $108 million extension in the following offseason.
The jump in ERA and FIP was due to more home runs, walks, and hits allowed, causing a steep ERA increase and a small FIP increase.
Due to Darvish having 11 pitches in his arsenal, it would be best to look at his results and not his uniquely massive pitch selection that may have caused them.
First, Darvish got pretty unlucky. Despite possessing similar exit velocities and launch angles as in the past, Darvish’s BABIP allowed jumped from .251 to .319, while his home-run per fly-ball% went from 10.5 to 15.0%.
Year-to-year variance in these numbers is very common, although not typically to this extent. This could be due to his slightly diminished stuff, as his average PLV dropped from 5.35 to 5.11. Still, Darvish’s unique ability to adapt as he has aged should be able to somewhat counteract this.
Darvish still allowed many more hitters to reach base via walk, which is something that could improve when fewer balls in play land for hits.
Darvish has seen career-worst strikeout numbers in recent years. Pitching to induce weak contact rather than strikeouts may be something Darvish has to focus on as he continues to age.
At 37, with five years still on his contract, Darvish can get back to being above league average with some natural regression and an improved approach to limiting walks. Avoiding injury would be important as well, as Darvish is already on the 15-day IL to begin the 2024 season.
Darvish is as smart of a pitcher as it comes. As long as he continues to adjust his game as his career continues, he will likely get back to being an above-league-average pitcher.
Joe Mantiply
Joe Mantiply was a wonderful feel-good story in 2022, as he made his first All-Star team and posted elite numbers for the first time in his career. At 31-years-old, Mantiply had a 2.85 ERA and 2.83 FIP over 60.0 innings.
Unfortunately, in 2023, Mantiply regressed significantly, posting a 4.62 ERA and 3.84 FIP over 39 innings. A shoulder injury to begin the year and a hamstring strain a little while later significantly hurt his numbers, but there were a few technical changes that didn’t help either.
Year-over-year variance is common in relievers, but Mantiply’s significant strides in generating strikeouts in 2022 failed to carry into 2023. In addition, his elite 2.5 BB% jumped to a slightly worse 5.7%, while his Barrel% and Whiff% regressed heavily.
A lot of this can be attributed to injury, as Mantiply dealt with shoulder inflammation to open the year and returned to the IL with a hamstring strain later on. These injuries may have contributed to his already slow pitches getting even slower, likely being the reason for some of his worse results. Still, Mantiply had some pitch decisions that likely hurt him as well.
Data via Baseball Savant (dotted circle = league average)
Despite his slower pitch speeds, Mantiply has unique movement on his pitches that allow him to generate high groundball rates and, when he’s on, weak contact.
His curveball and changeup in particular have excelled, and despite his poor overall numbers in 2023, they got excellent results. Most of his damage came against his sinker and four-seamer, which both averaged about 90 mph.
In 2023, they were both up a tick, which could have been hurt by injury in 2023. Still, every mile-per-hour counts at those speeds.
While his sinker wasn’t great, Mantiply threw his four-seamer more often than in the past, which was not the right choice. Batters had a 1.000 SLG against the pitch and averaged a 96.0 mph exit velocity with a 29-degree launch angle on balls in play.
Since these numbers are so poor, I’d say Mantiply would benefit from simply not throwing the pitch at all. While it could be good to occasionally get a different look from his sinker at somewhat higher speeds, results like this are too bad to consistently use.
Instead, Mantiply could benefit from throwing his sinker less. For a pitch that hasn’t been nearly as good as his secondaries, it would likely help to throw his changeup and curveball more frequently to get the best out of his sinker.
James Paxton
James Paxton had an interesting 2023 season, posting a 4.50 ERA and 4.68 FIP in a full season’s workload after missing most of his prior three seasons with injury. While these numbers were some of the worst of his career, it was the first mostly healthy season Paxton has thrown since 2019 with the Yankees, where he had a 3.82 ERA and 3.86 FIP.
With such a large gap between real campaigns, it’ll take a lot for Paxton to consistently get back to what he once was. Instead, it’d be best for Paxton to focus on what he did well in 2023, and improve upon other parts of his game that he still can.
Across the board, Paxton was very similar to the past, just slightly worse. His strikeouts were down, home runs were up, and exit velocities increased. These trends aren’t a surprise, as Paxton is 35-years-old and coming off loads of injuries. In 2024, Paxton might have to change his approach a bit to get back to above-average results.
Data via Baseball Savant (dotted circle = league average)
Paxton uses his four-seamer a ton, and it didn’t net outstanding results in 2023. While in the past it hasn’t been excellent either, as Paxton eventually loses some stuff on the pitch, it could help to focus on his secondaries a little more.
His curve and cutter continued to be solid, but his changeup is an intriguing pitch. While it hasn’t consistently had great results, it’s always returned an oddly high Whiff%, which was at 46.7% in 2023. Stuff-wise, it’s a fairly normal changeup, but its infrequency of use and separation from his most common pitches may have led to the swings and misses.
Paxton also re-introduced a sinker in 2023, and while it was barely thrown, it could be useful in the future to keep hitters off of his four-seamer.
The Red Sox were infamous in 2023 for their high usage of four-seamers, which probably helped Paxton’s confidence in the pitch. In 2024, however, they have gained notice for new pitching coach Andrew Bailey’s staff-wide decision to limit fastball usage, which has generated great results.
Unfortunately, as Paxton has left the Red Sox for the Dodgers in 2024, he won’t be around for that change. Still, he is joining an excellent pitching coach in Mark Prior with the Dodgers, who has been notable for getting the best out of veteran pitchers over the year.
It remains to be seen what Paxton can do to defy the aging curve but with his previous track record, as well as a smart organization in the Dodgers, Paxton can certainly improve in 2024.