Here's a fun comparison-- Player A--started minor league career at age of 21, 292.1 IP, 3.66 ERA, 1.36 WHIP, 7.3 k/9, 3.2 bb/9, .4 HR/9 Player B--started minor league career at age of 18, 440.2 IP, 2.98 ERA, 1.12 WHIP, 9.5 k/9, 2.5 bb/9, .5 HR/9 Player A is Sonny Gray, player B is Berrios. Obviously there's no guarantee that JO will be better than, or even as good as Gray, the comparable minor league numbers sure indicate there's a damn good chance. Accordingly, I wouldn't trade Berrios for Gray straight up, let along adding Kepler in.