Buck: "J.A. Happ has become a strikeout pitcher, for sure."
Happ's seasonal k/9s:
11.25 (rookie year, 4 IP total)
7.39
6.45
7.21
7.71
8.96
7.48
7.58
7.90
7.52
13.11 (this year, only 11.2 IP to his credit)
That's.... pretty consistent excepting some level of random variance and small sample sizes. So if you're calling Happ a strikeout pitcher now, then by performance he's pretty much always been a strikeout pitcher.
What's really changed is the walk rates (from high 3s to low/mid 4s in his earlier seasons to sub-3 in 2015/16/17)