The MLB Rules Committee has determined that a legal catch has occurred pursuant to OBR 2.00 (Definition of Terms, Catch), or a valid force out or tag has occurred pursuant to OBR 2.00 (Definition of Terms, Tag), if the fielder had complete control over the ball in his glove, but drops the ball after intentionally opening his glove to make the transfer to his throwing hand. There is no requirement that the fielder successfully remove the ball from his glove in order for it be ruled a catch. If the fielder drops the ball while attempting to remove it to make a throw, the Umpires should rule that the ball had been caught, provided that the fielder had secured it in his glove before attempting the transfer. The Umpires will continue to use their judgment as to whether the fielder had complete control over the ball before the transfer.
This is the MLB rule which is what we play by except for the personalized rules CDMSBL has incorporated. This has been a point of contention since the use of replay was expanded this year.