He's had all of 26.2 IP to prove himself, and of those, 18.1 have been on the day he was called up, likely involving a very early flight, not much sleep, and in one case, lost luggage that required him to borrow someone else's shoes while he made a spot start. (Despite that, his career numbers are a FIP of 4.62, xFIP of 4.28, with 8.4 K/9 and 3.57 K/BB.) I do not understand how anyone can say his major league performance has been anything but a small sample, and with extenuating circumstances behind most of it.