"Johnson said. “He’s got the arm strength. He’s an explosive, athletic pitcher, which you don’t see very often. He’s got explosive legs, a quick arm, and his fastball sneaks up on you. He can get it up to 95 (mph), but he could be guy you see throwing 97 or 98 at some point.
“It’s there, it’s just a matter of developing secondary pitches, gaining some confidence, and having some more success,” Johnson said. “But he’s got a chance to be a real guy.”
Here is a link to some youtube video of him striking out Bryce Harper in February. The only problem is you never see him in the frame, just Harper.