To make room for Kuhl on the active roster, Pittsburgh optioned left-hander Kyle Lobstein to Triple-A Indianapolis. The Bucs also needed a 40-man roster spot in order to add Kuhl; to that end, they designated right-hander Curtis Partch for assignment.
The Bucs' No. 16 prospect according to MLBPipeline.com, Kuhl went 6-2 with a 2.58 ERA in 14 Triple-A starts.
In an unrelated transaction, the Pirates officially released left-hander Cory Luebke after he refused an assignment to Indianapolis. Luebke, who went 0-1 with a 9.35 ERA in nine appearances for the Pirates, was designated for assignment on June 18.