Indecisive or Good Umpiring

[njdevs00cup]

Last night I was the BU for game one of a men's league final series. During ground rules the home manager explained that the storage unit and batting cage in left-center field are played as fences. In the unfenced area between the unit and cage, if the ball hits the tree in the air, it is a homerun. If the ball bounces into the unfenced area it is a double. I've umpired at this field many times and was familiar w/ the ground rules.

I'm in A and the batter hits a shot to the open area. I button hook, watch the touch at 1B and see the ball hit the tree and roll into the unfenced area. I call a dead ball, the PU did not signal either way. The PU came out and said he thought the ball hit the tree and asked me if I saw the same. I agreed and the PU signaled homerun.

In light of the obscure ground rule, do you feel this was good umpiring or indecisive umpiring?