This story was excerpted from the Phillies Beat newsletter, with MLB.com's Jared Greenspan writing this version. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.
When the Phillies acquired Jesús Luzardo from the Marlins last December, it didn’t seem like the left-hander would slot into the team’s eventual playoff rotation.
But Philadelphia is now navigating the pennant race -- as it will October -- without its unquestioned ace, Zack Wheeler. On paper, the Phillies are as equipped as anyone to handle such an absence, thanks to an embarrassment of pitching riches. That includes the stability provided by Luzardo, who is hitting his stride at the perfect time.
Luzardo, 27, has pitched to a 2.64 ERA in an eight-start span since July 29, after tossing six innings of two-run ball in a win over the Marlins on Saturday. On the season, his 3.01 FIP is tied for seventh best among qualified starters. Of equal importance, Luzardo has made 29 starts -- one shy of the MLB lead -- and is on pace to pitch more innings in a single season than he has in his career.
Last year, Luzardo made just 12 starts, his season truncated in mid-June with a lumbar stress reaction in his back. In the offseason, he knew that he had to find a way to stay healthy. His solution? He lowered his arm angle. Below, you can see his arm angle upon release in 2024 (left) compared to 2025 (right).
“Last year, I raised it, and my back didn’t feel great,” Luzardo told MLB.com last month at Citi Field. “Going back to 2023, my arm slot was a little lower, and it was one of the best seasons I’ve had in the big leagues. I felt good all year. I’ve felt really good all year this year, as well. In terms of health, I feel like a lower slot helps me out. Trying to create more of an angle really messed up my back.”
Luzardo’s arm angle is six degrees lower than it was last season, scaling towards a more sidearm delivery. He’s thrown from a lower slot in the past -- including a 29° arm angle as a rookie in 2019.
But Luzardo had to work to get back to that point. He originally raised his arm angle ahead of the 2024 season in hopes of creating more vertical movement on his fastball.
“I was trying to improve my four-seam a little bit more, get a little bit more ride with it, understanding that the higher slot kind of creates more carry,” Luzardo said. “But at the same time, it kind of hurt me in other ways. I don’t regret trying it out, but I understand that that’s probably not the best move for me.”
It’s easier for pitchers to put backspin on the baseball -- which creates the illusion of rise -- from a more over-the-top arm slot. Sure enough, Luzardo’s fastball went from 14.1 inches of Induced Vertical Break (IVB) in 2023 to 15.4 inches in 2024. But Luzardo still had below-average vertical movement on his fastball, and the raised slot wore down his body.
“Going back to what made my pitches feel good, from a lower slot, throwing a sweeper now, it just made more sense to drop back down a little more normal and take some pressure off my arm,” Luzardo said.
That’s the second key to all of this -- Luzardo’s new sweeper, a variety of slider with more “sweeping” horizontal movement.
In the offseason, Luzardo wanted to add a pitch to his arsenal. Up to that point, he had three pitches -- a four-seamer, sinker, and changeup -- that ran arm-side, as well as a bullet slider with very tight movement. He was missing a pitch to break away from a left-handed batter and in on a right-handed batter, something with more glove-side movement.
“I never really had anything like that,” Luzardo said.
Shortly after the trade, Phillies pitching coach Caleb Cotham asked Luzardo if he had ever tried a sweeper. Luzardo hadn’t. But Cotham’s suggestion kickstarted Luzardo’s imagination, and the pitch developed from there -- first in catch, then in bullpens, then in Spring Training. In his first start of the year, the sweeper keyed an 11-strikeout outing.
“It just slowly progressed into something that I knew could be a weapon,” Luzardo said. “And the lower slot helps me go a little more east-to-west. It gives me a little more of an angle, especially on left-handed hitters, and maybe a little more crossfire on righties.”
Luzardo’s recent success coincides with the sweeper’s emergence as the No. 1 option in his repertoire. In August, he threw the sweeper 38.5% of the time -- more often than his fastball. Opponents are hitting just .175 against the pitch this season, with a 43.6% whiff rate good for the third highest induced by any sweeper in baseball (min. 100 swings).
Luzardo, rightfully so, refers to his sweeper as a “consistent weapon.” But developing a new pitch is often easier said than done. There were a good deal of growing pains, too.
“I went through a period in the middle of the year where I wasn’t really throwing it for strikes,” said Luzardo, whose sweeper saw its zone rate crater in July. “It was kind of sporadic. The movement was all over the place. It had some depth sometimes, sometimes it didn’t. So we’re back to having consistent movement, which is easier for me to understand how I can throw it and where I can throw it.”
With an average of 8.8 inches of horizontal break, Luzardo’s sweeper has 3.3 fewer inches of horizontal movement than comparable sweepers. So while it’s not the most “sweeper-y,” it is within the context of Luzardo’s arsenal, with sharp, extreme movement in the opposite direction of his four other pitches.
Early on, Luzardo relied on his sweeper to induce chase from left-handed hitters, while using the pitch to pepper the zone against right-handed hitters. But lately, he’s been able to use his sweeper for both purposes against both -- righties actually had a higher chase rate off his sweeper than lefties in August. It’s another example of his newfound confidence in the pitch.
All of this success comes back to his lowered arm angle. It’s easy for us to write about a change like this, just as it’s easy for pitchers to talk about it. But what’s it like actually overhauling your arm angle and getting it to stick?
It took Luzardo countless repetitions to rewire his muscle memory. During the season, he relies on his coaches, who use tracking data to see if his arm angle is creeping up or down. If they notice something, they’ll inform Luzardo, who will adjust accordingly. While Luzardo hasn’t looked at the data himself, it’s a form of insurance. At this point, he’s developed a natural feel for where his arm should be.
“It’s about making a conscious effort,” Luzardo said. “I think, at this point, we’ve thrown so many pitches that you kind of understand. You know, as you creep up, maybe you feel a little more stiffness in a certain area.
“... Everyone’s going to have a degree or two up or down, depending on how you feel that day. But for the most part, it’s been really consistent. Like I said, I think it’s just wherever my arm feels best is where I’m going to throw it.”
That simple motto has refined Luzardo into a playoff caliber arm.