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Unable to pinpoint the common denominator for the reasons behind his effectiveness plunging, his ERA spiking and balls flying out of the park so often in June, Cardinals’ left-hander Matthew Liberatore is hoping to have time to do a deep dive on his pitch arsenal before his next start.
Whether that next start will come with the Cardinals – or potentially with Triple-A Memphis – remains to be seen because the left-hander has been in the kind of tailspin of late that might be too steep to pull out of against big league hitters.

For Liberatore, a June swoon has clouded a season where he was named as the Cards’ Opening Day starter and expected to be a staff leader. Over his last four starts, Liberatore has allowed 18 earned runs and seven homers. The 10.34 ERA in the month has pushed his ERA for the season to a career-worst 5.56, and the seven long balls have taken his total of homers allowed for the season to 17. After holding foes to .293 hitting in April and .283 success in May, foes are hitting .338 against him in June.
What has been particularly galling to Liberatore, 26, is how he has allowed games to get out of hand with big innings for the opposition. He gave up three runs and two runs in consecutive innings against the Reds on June 6 and allowed four runs over the fourth and fifth inning against the Twins on June 13. The bottom fell out over his next two outings, with the Royals hammering him for six runs in the second inning last week and the Dbacks hanging up another six runs in Wednesday’s fourth inning.
“That’s kind of what we’ve been talking through and that’s what I was talking to (catcher Pedro Pages) about — there’s not necessarily a common denominator with the ways that I’m getting beat and each time that (big) inning is different,” he told reporters on Tuesday night following the Cardinals 9-4 loss to Arizona. “I’m sure at some point we will find that common denominator and I’m hungry to do that because I’m tired of pitching like this.
“I believe I’m better than I’ve done over the last month, for sure. But as of right now it’s still an unknown and something we’re going to figure out.”
Weather permitting, the Cardinals (42-36) will begin a three-game series against the Marlins (42-39) at Busch Stadium on Friday night. After dropping two of three games to the Diamondbacks, the Cards dropped from the top Wild Card slot to the No. 3 spot, just 1 1/2 games ahead of Miami.

One place for Liberatore to look for clues is in the heart of the plate. He grooved a 0-2 curveball to Ildemaro Vargas, who drilled a 99.4 mph double down the left field line to plate two runs. His next pitch – a 90.5 mph cutter – also split the plate and LuJameds Groover crushed it for his first MLB homer. Two pitches later, another Liberatore pitch that got way too much of the plate also ended up in the left field seats – this time Ketel Marte hitting a 109.3 mph missile that traveled 416 feet.
“A six-run inning puts the team in a hole again and that was pretty much the whole story,” Liberatore surmised.
According to Baseball Savant’s Pitching Run Value, Liberatore’s pitches in the heart of the plate had a plus-6 rating in 2024. In 2025, they measured at a minus-1. This season: minus-8.

For the most part, the opposition is barreling up balls, hitting them 95-plus mph and hitting them on the ground at equal rates in 2026 as 2025. The areas of the biggest spikes have come in pull rates (from 36.9 percent to 44.1 percent), pulled-in-the-air rates (from 15.4 percent to 22.7 percent) and in terms of solid contact (5.0 percent of the time to 6.1 percent of the time).
Overall, his Pitching Run Value (minus-18) and Breaking Ball Run Value (minus-9) rank in MLB’s bottom one percentile, while his Fastball Run Value (minus-10) is in the bottom five percentile. His best pitch has been his changeup, which ranks in MLB’s 66th percentile.
Lefties have clipped him for a .316 batting average and six homers, while righties have feasted to the tune of .297 and 11 homers. Of his 17 homers surrendered, Baseball Savant categories eight of them as no-doubters.
Again, Liberatore is trying to evaluate whether it’s the shapes of his pitches, his sequencing of pitches or poor location that is leading to his sudden struggles.

“I still have confidence in my stuff, and I still liked how I threw the ball outside of that fourth inning,” Liberatore said of his latest lopsided loss. “We had some things that we were working on coming into this start, and I feel like I did a really good job executing on all of them. But I had an unfortunate fourth inning.”
One potential option for giving Liberatore more time to get back on track could be Triple-A lefthander Brycen Mautz, who was scratched from his scheduled start for Memphis on Thursday. Mautz, who was promoted for his MLB debut on May 24 only to see his scheduled start washed out by rain, is 0-2 with a 2.45 ERA over 13 starts this season with Triple-A Memphis. He has struck out 62 batters in 58 innings of work.
As for Liberatore, he hopes he can uncover why his starts keep getting derailed by one big inning.
“I’m getting ahead of guys, I’m landing both of my breaking balls and my shapes and velo are really good,” said Liberatore, whose strikeout rate has risen from 18.8 percent in 2025 to 20.2 percent in 2026. “I feel good about the way I’m moving and I’m executing at a high level. The problem lies within those pitches that I’m not perfectly executing. Sometimes, I’m getting burned on the pitches I do execute on. So, it’s a little mixture of both.”

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