We don't get a lot of chances to hear the coaches talk about low-level minor league pitchers, but here, Tony Fossas goes into detail about Corcino, Lotzkar, Tuttle, Robles, Johnson, Howell, Wolford, Guillon, and Correa. He also talks about Joseph and his time tutoring Chapman. He really speaks highly of Blaine Howell and Ismael Guillon. The whole interview is long, about 25 minutes.
For those who saw Joseph pitch in Dayton, you will note his comment that he has "better than a major league slider" and that "I can't think of any left-handed hitter that can hit his slider."