Brandon Eisert

Eisert returns to Pittsburgh’s bullpen equation with Isaac Mattson hitting the injured list. The 28-year-old southpaw has made nine appearances for the Pirates since being acquired from the White Sox in mid-July.

Eisert threw 28 pitches over the last two games against the Giants and is likely just being exchanged for a fresh reliever here.

Eisert has a 6.29 ERA, 1.40 WHIP, and 40/12 K/BB ratio in 34 1/3 innings between the White Sox and Pirates this season. He’ll give the Pirates some added bullpen depth over the final month.

Eisert heads back to the minors with Pittsburgh clearing space for relievers Lake Bachar, Luke Weaver and Kirby Yates on their active roster. The 28-year-old’s latest stint in the big leagues lasted roughly 24 hours.

Eisert gets the call to replace an injured Mitch Keller (shoulder) on Pittsburgh’s roster. The 28-year-old lefty reliever was picked up from the White Sox in a trade last month.

Eisert threw 2 1/3 scoreless innings on Tuesday, but the Pirates have no off days until August 10th, so they can’t afford to be down a bullpen arm for the next few days. Eisert will be back up again soon.

The 28-year-old southpaw has struggled in his time with the White Sox this season, posting a 5.93 ERA, 1.24 WHIP and a 32/8 K/BB ratio across 27 1/3 innings in his 25 appearances. He should still help to stabilize the middle of the Pirates’ bullpen given their recent struggles. The Pirates will have to make a corresponding move on Saturday before he’s added to the active roster.

Eisert returns to the big leagues after spending a couple weeks in the minors after a pair of rough outings for the White Sox back in mid-April. The 28-year-old southpaw holds a serviceable 4.75 ERA across 78 2/3 innings for Chicago over the last two years.

Eisert pitched on Sunday and again on Tuesday, allowing four runs on six hits in 2 1/3 innings. The White Sox will get a fresh arm up in the pen.

Eisert, 28, was a fixture in the White Sox’ bullpen throughout the 2025 campaign, registering a 4.39 ERA, 1.44 WHIP and a 74/25 K/BB ratio across 69 2/3 innings in his 72 appearances. He’ll function in a middle relief role.

Eisert will likely be one of the first relievers back up for Chicago when they need bullpen help. The White Sox are going to need a lot of bullpen help.