If there is truth to the rocket ball having a smaller thread height, Porcello is exactly the type of pitcher who could see the worst negative effects. He doesn't throw exceptionally hard so as to blow his fastball by hitters, and his heavy reliance on the two-seamer could be problematic. The reduced thread height would mean the pitch broke less away from right-handed hitters, making it a straighter low 90's fastball. That type of pitch gets punished in MLB, unless you have an excellent changeup to keep hitters off-balance.
Porcello's offspeed offerings are probably breaking less due to the reduced seam height, making his sinker basically the same pitch as his changeup, and his curveball would hang a lot more often. He's already given up more flyballs than he did all of last season...