Control of line drive?
 

Ball hit to 3b, lands in glove, glove comes off fielder's hand but stays in glove, . What do we have?

Did the glove with the ball in it touch the ground or some object on the ground?

I apologize for the haziness of the original post. This was a line drive hit to 3B, "caught" by the fielder. However, the impact of the ball was forceful enough to immediately cause the glove to come off the fielder's hand and land on the ground with the ball in it.

No catch. The fielder failed to control the ball. The fielder would need to voluntarily release the ball, or else attempt to transfer the ball to her throwing hand and drop the ball then, for it to be a catch.

Once the glove with the ball (and without the fielder's hand) in it touches the ground, a catch is no longer possible. The ball has touched an object on the ground, and was never controlled by a fielder.

If the glove-and-ball combination had instead popped into the air, it could still be caught by the same or another fielder.