[greymule]

Yes, my MLBUM says that first part, but it doesn't say, "A fielder leaving the field of play with possession is the same as deflecting it since it was his impetus that made the ball leave said field of play and become dead."

mcrowder cited the MLBUM as instructing "treat as a caught ball," which is quite different.

In the rule book, I can find only "falls into a bench or stand," "falls across ropes into a crowd," "should fall into a stand or among spectators or into the dugout or any other out-of-play area, [my emphasis]" and so on. It seems to me that falls is in all those examples for a reason. I don't see "enters DBT" or "leaves the field of play" anywhere (in OBR). Several case plays indicate that a fielder can indeed carry a ball into DBT and then make a throw.

For what it's worth, I queried "Hal the Referee" of the Cleveland Plain Dealer 30 years ago about a fielder making a catch, leaping a fence, remaining on his feet, and making a throw from "Row F" of the stands. The answer was "Yes, that's legal."