I think the rollover feel/cue is a short cut to 12/6 spin for those that struggle getting it with their FB. I don't think its just a follow through. I think those who use I/R mechanics with their 12/6 fastball (thanks FFS) are mistaken for throwing a rollover. I'd guess that many believe the peel must be thrown with the palm facing forward and staying palm forward in follow through to be a true peel. For them, any natural rotation of the hand in follow through is a rollover.
As I was learning with my kids, I found I struggled with getting a 12/6 FB. The rollover feel/cue worked for me to get 12/6 spin. Since, I've been able to get a 12/6 other ways, but the rollover feel is still the easiest.
As I was learning with my kids, I found I struggled with getting a 12/6 FB. The rollover feel/cue worked for me to get 12/6 spin. Since, I've been able to get a 12/6 other ways, but the rollover feel is still the easiest.