How Concerning Is Jameson Taillon's Home Run Problem?

The initial stat line from Wednesday's start looked find for Chicago Cubs starting pitcher Jameson Taillon. The righty logged six innings and allowed just four hits while racking up seven strikeouts. The outlier was three of the four hits allowed went for solo home runs, which continued a pattern so far this season with the veteran pitcher. So, just how concerning is the home run ball becoming for Taillon?

For a reference point, Taillon allowed 21 home runs last season across 28 starts and 165 1/3 innings. He's set to exceed 21 home runs allowed this year by the time we pull the curtains down on the month of June. Taillon had just come off a start in Queens where he allowed four home runs in four innings in a loss to the Mets. For those who want to provide an escape path and point out the heavy hitters in the Mets lineup, two of the homers allowed came off the bat of Brett Baty and Jeff McNeil, who have a combined seven this season (though, in fairness, Baty was on a heater during that entire series).

Speaking with reporters after Wednesday's start against the Marlins, Taillon noted he believes he gets into a mode where he throws too many strikes, which could be contributing to the problem.

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"If I'm filling up the zone and working fast, we’ve got a great defense, Taillon said after Wednesday's outing. "I like taking our chances there. But, I think there are times where, let’s use that good command and expand. Use that good command to not throw strikes all the time. Sometimes I get into that strike-throwing mode, where it’s almost hard for me to change my release. That’ll just be something we work on.”

Taillon has always been tremendous at not allowing free passes, and so far this year, he's allowed more home runs (13) than walks (nine). Of the seven homers allowed in the last two starts, six have come from left-handed hitters. Teams will continue to stack lefties against Taillon, though he sees this as just a little bump in the road.

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"I was doing pretty well, and then the last two starts it hasn’t been so good against lefties,” Taillon said. “I think it’s just understanding what pitches I give up slug on to lefties. I’ve given up a lot of homers on the fastball lately, so it’s understanding my changeup’s gotten a lot better, my curveball doesn’t give up a ton of slug."

When honing in on other issues, there's another glaring set of numbers that sticks out. Per Baseball Savant, Taillon has a barrel percentage is the seventh percentile in all of MLB.  Digging deeper into that number, Taillon has allowed a barrel rate of 13.2%, which would be the highest in his career. Taillon's career barrel percentage allowed is 7.1%, making what he's allowed in 2025 almost double his career average. On top of that, Taillon currently has a hard-hit percentage of 42.1, also a career high. His career average in that department is 36.4%. 

Fortunately, fastball velocity hasn't been an issue for Taillon, but the usage could be an underlying problem. In 2024, Taillon used his four-seam fastball 29% of the time and it had a run value that chilled in the 97th percentile. This year, he's using the 4-seamer 41% of the time, and the run value has plummeted 7th percentile. Hitters are getting a better look at the pitch because it's being used way more frequently by Taillon, and as he noted Wednesday, he's been using it in the zone too much.

What's fascinating about all this is how well the uptick in the four-seamer has worked for Colin Rea. Rea used his four-seam fastball 20% of the time with Milwaukee in 2024, and it had a run value in the 11th percentile. This year, he's pumping that same pitch 53% of the time, with a run value in the 76th percentile. Rea has also tinkered with his arm angle—after being at 35 degrees in 2024, he's now releasing pitches at a 30-degree angle in 2025. The point remains that the high usage of the fastball for Rea has worked out tremendously this year, while Taillon has had different results.

It's not time to push the panic button on Taillon. He's a veteran who has settled into a nice role in the middle-of-the-rotation the past couple of seasons. Certainly, Chicago and the veteran are aware of the issue and will plug away at a solution. Taillon has always been working on his lefty problem — perhaps a simple change in his approach is all it will take to get him back to mid-season form.