When Jerry Rice came into the league his one greatest weakness, according to himself (along with others) was his hands.
He worked on them, and had a pretty decent career.
Cooper used to drop one every now and then, too.
Good coaching (from his position coach and Cooper; doesn't matter where it comes from, hand strengthening exercises for the S&C unit or Cooper: doesn't matter where it comes from) and extra time with the jugs machine and his QP (I bet Matthew would be willing) should more than address the physical component of too many drops.
Those exercises will also help to internalize internalize the mindset that catching the football
completely is important.
The drops I've seen Puka make seem n more a matter of concentration - fully securing the ball in traffic before doing anything else, and then making that split-second decision as to what to do with it next. The flip is the difficult balls, like a one-hander a couple of games back, that I've seen him catch. He's innately capable of it - the rest is just drillwork, which in his case is as much mental as it is physical.
