"Another possibility is that he loses some speed and twitch reflexes but gains in power. There are many examples ofplayers who hit 20-30 Hrs in their 20's then hit 30-40 from 30-35 or later."
Moon, you just described Hank Aaron. The Hammer is also the first guy I thought of most comparable to Mookie, when I first watched those quick lethal wrists turn on a fastball. If the Red Sox are betting on Betts to sustain greatness like Aaron through his 30s -- they are both listed at 180 pounds on baseball-ref -- then back up the truck. Someone will...