Game Situation: First Baseman Drops Ball

 
The shortstop fields a routine ground ball and throws over to first base in order to retire the batter-runner. Before the runner arrives at first base, the first baseman stretches and then catches the throw with his foot clearly and firmly on the base.
 
However, as the first baseman takes his first step to gain his balance, the ball accidentally drops out of his glove and onto the ground -- and then the batter-runner touches and crosses first base.
 
The offense coach thinks that this a muffed catch and his batter-runner is safe at first base. The defensive coach argues that his first baseman had the ball in his glove with his foot on the base before the batter-runner arrived at 1st base, so the batter-runner is out. What should the umpire call?
 
Call
Admittedly, it would best to actually see the play below to determine if the play was complete before the ball fell from the first baseman's glove. However, a few things to consider:

- The fielder did momentarily have control of the ball, but "momentary" control does not define a catch.
- The fielder did not voluntarily release the ball and he was not reaching into his glove to retrieve the ball.
- Is that first step off the base (after the ball goes into the glove) a part of new movement unrelated to the catch or is it part of the catch?
- Regaining balance is considered part of the catch.

For those reasons, it is likely that the first baseman did not catch the ball and the batter-runner is safe. You may want to review rule 2-9 and casebook plays 2.9.1a and 2.9.1b.