Even pre-injury, his minor league seasons hadn't profiled him as a can't-miss front of the rotation starter. For that, you kind of want to see him a little young for his league level and still dominating - he didn't do it. Putting up an ERA in the high 4's at AAA at age 23 isn't bad at all, and suggests a productive major league career; but that's what might be meant by "a 4 or maybe an ok 3".