McKenna will play 2021 at 24 years old(If they play). He will probably begin at AA. He has time to improve. But to move up he has to hit. Good defense is important but if he doesn't hit he will not go very far.
@DrungoHazewood you can add Earl and Sparky Anderson to baseball managers that looked a lot older than they really were.
50 today isn't the same as 50 30-40+ years ago. I'm not sure why that is. Maybe we know how to take better care of ourselves and there's more of an emphasis on fitness and nutrition than there was back then. It didn't take long, but people in their 50s these days definitely don't look the way people in their 50s did a generation or two ago.
If you're a modern pitcher and you're upset about getting yanked in the 7th inning of an early April start on three days rest, after the last two batters hit line drive at'em balls then maybe you need a time machine to 1978.