Kimbrel's walks are up but not wildly [5.3 vs 3.8 career]. Being 36 with 15 seasons under his belt is the more likely culprit. Blass, as a 30 y/o, finished 2nd in the 1972 CY voting (to Steve 27-10, 1.97 ERA Carlton). Up to that point his career walk rate was 3.0. In '73 the walk rate shot up to 8.5, the ERA from 2.49 to nearly 10.00, and his wins fell from 19 to 3. He pitched once in '74, walking 7 in 5 innings, and his career was over. That's quite a different animal.