Bullpen Pitcher Fields Ball

[JJ]

In NCAA, I would apply Rule 4, Section 8, which says, "If there is interference with a live batted or thrown ball by anyone other than players, coaches, or umpires, the umpire shall rule as to it being intentional or unintentional.
a. If it is intentional, the ball shall be declared dead at the moment of the interference and the umpire shall award the offended team appropriate compensation that, in his opinion, that would have resulted had interference not taken place."

From where I sit, a pitcher warming up in the bullpen is not a player - he's a potential substitute.

I would apply the same logic in Pro rules as well (though of course I could not cite the NCAA rule).

JJ