Illegal First Baseman's Glove?

 
With the bases loaded and no outs, it looks like a sacrifice bunt or a suicide squeeze could be on tap.
 
The first baseman moves in towards home plate and the second baseman drifts over closer towards first base. The offensive coach sees that the second baseman is actually closer to first base than the original first baseman, so the coach requests "time" and wants the umpire to have the original first baseman remove his first baseman's glove and replace it with the usual sized fielder's mitt.
 
What does the umpire do now?
 
Call
In NF (and only NF), there are two types of gloves -- fielder's mitts and the catcher's mitt (NF 1-3-6). If a mitt is a legal size to use at first base, it is legal size to use at any of the other 8 positions.
 
In the situation below, the first baseman and second baseman can use any legal sized mitt (see casebook play 1.3.6C). In addition, this is a legal defensive shift and the players did not officially change positions. There is no action needed by the umpires.