Kansas/Baylor Throw-in Question

[referee99]

Great game. B-V, 3-person. Overtime game, under a minute, home team A1 nails a shot to go up 4 with 25 seconds left or so.

B2 with body language of disappointment and confusion picks up ball, and with foot partially on court, partially out-of-bounds passes the ball to teammate. I whistle violation.

Not a call I want to be making at the end of a great game, but I didn't see another option. The kid violated.