5 MLB pitchers who are underperforming heading into June

Welcome back to another analysis of five MLB pitchers in the 2026 season. This week, we’re back on the underperformers. From ERAs sitting near 9.00 to SIERAs hovering around 3.00 and expected wOBAs far beneath their real marks, we’ll examine which pitchers have been underperforming due to weak contact finding holes, bad sequencing, and other misfortunes that suggest they should be pitching better than they are.

MORE: 15 MLB teams currently under the newly proposed salary floor

Visit michezonews.co.za for more information.

Tyler Mahle, San Francisco Giants

MLB May 20, 2026; Phoenix, Arizona, USA; San Francisco Giants pitcher Tyler Mahle (54) throws in the fifth inning against the Arizona Diamondbacks at Chase Field. Mandatory Credit: Matt Kartozian-Imagn Images

Leading off this week is San Francisco Giants right-hander Tyler Mahle, whose 9.00 ERA over his last three starts is one of the most misleading lines in baseball. Across 14 innings, Mahle has allowed 14 earned runs, but his 2.60 SIERA tells a completely different story. The contact against him has been weak, with a 31.9% hard-hit rate, a 4.3% barrel rate, and an 85.9 mph average exit velocity, all well below league average.

His .405 wOBA against sits 131 points above his .274 expected mark, and a .383 BABIP shows balls dropping that shouldn’t. With a 22.7% strikeout rate and a 6.1% walk rate, Mahle’s ERA should plummet toward his skill level soon.

Janson Junk, Miami Marlins

Next up is Miami Marlins right-hander Janson Junk, who carries the largest sample of bad luck on this list. Over his last three starts spanning 15.1 innings, Junk has surrendered 16 earned runs for a 9.39 ERA, but his 2.93 SIERA says he has pitched far better than that. The contact against him has been manageable, with an 86.7 mph average exit velocity and a 6.6% barrel rate, and he has barely walked anyone at 4.1%.

His .440 wOBA against towers 132 points above his .308 expected mark, while a .361 BABIP confirms balls keep finding grass. If he leans on the soft contact over strikeouts, Junk’s results should normalize in a hurry. 

Peyton Gray, Texas Rangers

Over three short outings totaling just 5.1 innings, Texas Rangers righty Peyton Gray has allowed 8 earned runs for a 13.50 ERA, yet his 2.83 SIERA hints at a far better arm underneath. He has paired a 23.3% strikeout rate with a 3.3% walk rate, and the contact has stayed soft, with a 4.8% barrel rate and an 86.4 mph average exit velocity.

His .443 wOBA against runs is 145 points above his .298 expected mark. The more he keeps pitching, the more Gray’s ERA should crater toward his skill. 

Mitchell Parker, Washington Nationals

MLB May 29, 2026; Washington, District of Columbia, USA; Washington Nationals pitcher Mitchell Parker (70) throws to the San Diego Padres during the seventh inning at Nationals Park. Mandatory Credit: Brad Mills-Imagn Images

Washington Nationals lefty Mitchell Parker is another arm whose line lies about his week. Over his last three starts, Parker gave up 7 earned runs across 6 innings for a 10.50 ERA, yet his 2.93 SIERA points to something much closer to a quality stretch. His 23.3% strikeout rate and 6.7% walk rate are exactly the foundation you want, and his .425 wOBA against sits 117 points above his .308 expected figure.

The one wrinkle is a neutral .300 BABIP, so this isn’t a balls-finding-holes story. If Parker keeps missing bats and limiting free passes, his ERA should follow the underlying numbers down. 

Jose Quintana, Colorado Rockies

Rounding out the list is Colorado Rockies veteran Jose Quintana, whose home ballpark complicates the picture. Over his last three starts, Quintana yielded 11 earned runs in 11 innings for a 9.00 ERA, while his 3.48 SIERA points to a steadier performer.

His contact allowed has been roughly average, with a 36.4% hard-hit rate and an 87.2 mph average exit velocity. A .386 BABIP suggests some misfortune, though pitching half his games at Coors Field means a good chunk of that is the environment, not pure luck.

— Enjoy free coverage of the top news & trending stories on The Big Lead —

Read full story at source