7/14 update: Per Carlos Collazo, the Twins have reached an agreement with Stoffal. He will receive $150,000 in an underslot deal. The signing has not yet been made official by the Twins.

Operates from a really low release point 91-93 but can get fastball up to 95mph. 
Secondaries are a cutter/slider blend that he tunnels well with fastball and a good changeup with fade.

Weird look for hitters.