Two man umpire crew, nobody out runner on third. Fly ball to center, runner on third tags, runs home. Ball is cut.

Home plate umpire stays at home. Defense appeals, ump says runner left third early, calls him out.

My question: how can the umpire see the play well enough to make the call? From his position behind the plate, it seems to me he can't possibly see the centerfielder and the runner on third at the same time.

Depending on the exact location of the ball and the PU, you could be 100% right. There is no need to guess or use peripheral vision.

PU should take as deep a position outside the foul lines (toward the backstop) as possible where the V is 3B and the the ball being caught and he is the point or base of the V. From that position, he can time the catch and R's departure and return to the plate for incoming.

It is the PU's call all along. He has to move back and down the line to get the best look. Will he be right every time, maybe not. If you want it better, hire a third ump. This is one of the limits of the two man system. I manage my son's Pony team and I was on the short end of similar call Saturday. R2,R3 and one out. Fly ball to right, which was touched and dropped. R3 came home without tagging. The other team got a double play. PU had a catch so I was out of the inning.

When I am the PU, in my pre-game "conference" with the BU, I tell him that I will watch runners at 3b for tag plays. When the catch is made in the outfield, the BU should yell "out", or "catch". With his voice, and my eyes, we have it covered. We work together as a team, not independently.

hatman:
Don't use your partner's voice to determine leaving early. He has to make sure he doesn't drop it. The runner can leave on first touch. Most of thime it doesn't make a big difference but it will always make some.

So if the ump just stayed put behind the plate, without moving to take an angle from where he could see the catch (straightaway center) and third base - then he can't really make the call?

I'm not saying he can't make the call but he sure will make it harder.