ペンサコーラ・ブルーワフーズ
To begin the 2021 season, Guenther was assigned to the Pensacola Blue Wahoos of Double-A South. In 17.2 innings with Pensacola, Guenther posted a 1-0 record with a 1.02 ERA and 28 strikeouts. On June 8, Guenther was promoted to the Jacksonville Jumbo Shrimp of Triple-A East.