MILWAUKEE — Two days before the MLB trade deadline, the Chicago Cubs are swapping out an arm in their bullpen.

The team announced Tuesday that it had designated right-hander Chris Flexen for assignment and recalled right-hander Gavin Hollowell from Triple-A Iowa.

Flexen had been a surprising and solid contributor to the Cubs’ pitching staff this season. Signed to a minor-league contract with an invite to big league camp in spring training, Flexen began the year with Iowa before joining the Cubs in late April.

The 31-year-old right-hander then began an impressive start to his Cubs career. He tossed 21.2 innings across 12 appearances without allowing an earned run, eating multiple innings as he provided cover to manager Craig Counsell’s bullpen.

Flexen surrendered two earned runs in a June 22 loss to the Seattle Mariners, but he then threw six scoreless innings across three appearances, including four shutout frames against the Houston Astros.

Flexen relieved Drew Pomeranz on July 5 after the left-hander served as the opener against the St. Louis Cardinals and allowed a run on four hits in 3.2 innings.

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But things started to unravel for Flexen after that.

He was slotted into the rotation following Jameson Taillon’s calf strain and allowed three runs in a four-inning start against the New York Yankees. He allowed runs in his final five appearances with the Cubs (7.98 ERA in 14.2 innings).

As the Cubs seek pitching help ahead of Thursday’s trade deadline, someone like Flexen was under the microscope. The Cubs would need to make both 40-man and 26-man roster moves to accommodate any additions.

Hollowell, 27, has appeared in five games for the Cubs this season and posted a 1.42 ERA across 6.1 innings. He has a 5.24 ERA in 20 games for the I-Cubs with 34 strikeouts in 22.1 innings.