If Soroka really is sitting 90-91 with his FB, then he is succeeding with mediocre stuff against low quality hitters due to superior command vs his level.
I hope we have witnessed this exact phenomenon enough times to see where this is probably going: getting shelled at the MLB level.
FB velo sitting at 90-91 simply isn't going to allow him to be anything more than a backend guy. Hooefully there is more in the tank from him.
Now bring on the homers with their chats of "he just knows how to pitch", and "he just hits his spots", and "he just knows how to change speeds". They were wrong every other time they've spouted that nonsense, but that certainly won't stop them from doing it again.