The White Sox shook up their starting rotation Friday, optioning Jonathan Cannon to Triple-A Charlotte and recalling right-hander Wikelman Gonzalez, who was acquired as part of the Garret Crochet trade over the offseason.

Gonzalez has already thrown five innings out of the bullpen for the White Sox this season and has served exclusively as a reliever for the Charlotte Knights. This leaves the door open for one of the White Sox’s newly acquired prospects, such as Duncan Davitt, to join the starting rotation. However, the team has yet to announce who will fill Cannon’s role in the rotation.

Cannon has struggled this season to the tune of a 5.34 ERA. During his last start in Seattle, he was tagged for seven earned runs on four hits and three walks before being pulled from the game in the second inning.

Traffic on the basepaths has been a recurring issue for Cannon this season, even with a walk rate of 8.2%, which is slightly better than the league average. Opponents are batting .274 against him. Despite having a five-pitch arsenal with a lot of movement, he has also struggled to miss bats.

His chase rate, whiff rate, and strikeout rate all rank in the bottom 20% among MLB pitchers, while opponents have an expected batting average of .284, placing him in the league’s bottom 12th percentile.  In his last seven starts, Cannon has posted a 6.68 ERA, allowing 37 hits with 14 walks and 25 strikeouts during that 32.1 inning stretch.

His low ground ball rate has also posed issues in a hitter-friendly home ballpark of Rate Field. These issues have prevented Cannon from being able to work deep into games consistently. Of his 19 appearances this season, 17 of which have been starts, Cannon has only made it through six innings in eight of them, averaging just five innings per outing.

Cannon now holds a career 4.86 ERA over 220.1 innings across two seasons with Chicago, leaving his future in the rotation uncertain for the time being.