Mavis Graves gets an in-depth look from Baseball America's "StatCast" column. Snipping some sentences rather than posting entire write-up:
We see a true five-pitch mix, headlined by a four-seam fastball that is not a very good pitch from a stuff perspective with below-average shape at only 91 mph. His sinker also looks like a below-average pitch with the current shape and velocity. So why am I writing about Graves? His changeup has gotten a 50% whiff rate against righthanded batters so far this season, and he mixes it in about the same amount as his sweeper and slider, which are currently getting 46% and 39% whiff rates against righties.
His gyro slider has chewed up lefties, with a 70% whiff rate. His sweepier slider hasn’t been nearly as effective. I like the building blocks for Graves. He has a complete arsenal as long as he can fix one of his fastball shapes, most likely the sinker.