He was kind of an unknown going into last season. Even this year he was as the 6th best prospect in the A's organization by Baseball America (2nd by Mlb.com). He would move up to 4th due to Peacock and Cole being traded, but it seems like Baseball America still isn't too high on the guy.
I don't believe he has the upside of a true number one, though I will admit I have never watched him pitched. From the numbers, I think he has #2 upside and more than likely will settle in as a #3. Now maybe I am underestimating him, like most scouts, but while his strikeouts have gotten better as he moved up through the minors, his ground ball rate got worse. It should also be noted that while it shouldn't be a huge issue, his walks did get slightly worse since High A. Also, while his ERA looked okay during his brief stint at the end of last year...he got lucky to get that. It's a small sample size, so you can take it for what you want (or don't)...but his FIP was 6.48 and xFIP was 5.30.
I like this guy late in drafts, because he should still be under most people's radars...but I don't see him starting with the team either. But with the amount of young pitchers they have and some of their injury histories, it won't be too long. If his walk and ground ball rates get back to where they were in the minors (even without getting his strike out rate back to one per inning) he should be a very good value.
Too second the part where you have never seen him pitch, I watched most of his starts at the end of last season and let me tell you the kid looks like he will be good. He can locate his fastball and do it around 93-95 mph. His changeup is above average and was sitting on 83-84. His slider is an excellent pitch and I watched him sit a couple of Blue Jays down in his debut.Not sure the speed of his slider but i would say its better than the changeup and gets a better k rate than the fastball, but is not his primary pitch. Only bad thing about his fastball is that hitters had a .310 avg on it. It may seem high but he only had 7 starts so that wouldn't get evened out.Other than that he looks like a solid pitcher. Number 1 pitcher in the organization? I don't quite agree with that because of the talented Tom Milone and Jarrod Parker.