Per statcast, his cutter and slider don't break enough anymore so he's leaving them over the heart of the plate.
https://baseballsavant.mlb.com/savant-player/eduardo-rodriguez-593958?stats=statcast-r-pitching-mlb
The slider seems to be just a "show me" pitch, but it's getting wacked around whenever he tosses it. Dropping the slider and sticking with a FB, Cutter, Change, Sinker mix should be enough. The slider should only be used if he's going to throw it out of the zone.