Jerseys during Warm-ups

[frezer11]

Had something last night I've never seen before. Are players required to wear their jersey during warm-ups? I didn't find anything that requires it. We had a player that went through his full warm-up, up to about 1:00 before tip off, in just his compression undershirt. While it seemed wrong and didn't pass the common-sense test, I didn't have definite knowledge, so let it go, and then couldn't find anything in the book that said they had to have it at that time. Has anyone ever seen that?

Nearest I could find was that the game jersey shall be tucked in to the game shorts, which would obviously require one to be wearing a game jersey. But I believe this is only for players (i.e., after the game has begun.)

In hindsight, maybe I'd pull the old 2-3, go put it on and continue the warm-up.