There have been many times when I felt - and many others I've heard make similar comments - that the field ump is out of position to make the correct call. Here are two situations.
1. R1 on third. The field ump is positioned behind third base and a few steps away from the foul line.
2. R1 on first. The field up is behind second, a few steps shaded toward first.
In example (1), I feel that the plate ump has the runner on third, and the field ump should be over at first.
In example (2), I feel that the field ump should be closer to first than second, and ready to run over to second if a play develops there.
As my ASA ump friend says, "They should be following the ball." But I think some field umps are lazy and don't want to run to the play, so they cheat a little and try to cover too much with the least amount of movement. I don't mean to be discriminatory here but it seems the field umps that have more girth seem to be the laziest.