Arkansas #70 put on a jersey with #41, making him an eligible player. The referee announced this change. What I would say is that "Arkansas #70 is now wearing #41."
Yeah, I didn’t actually see the Arkansas player wearing either number, so I couldn’t connect the R’s announcement with what I could see. But, later, an LSU player changed numbers, as well, and I actually saw that player with the changed number, so it became obvious that they had actually changed numbers. And that’s all OK. The announcement just confused me.
To answer Bama’s question, yes, it is a UNS to change your number to something other than what is on the ‘game day roster’ -and enter the game - without reporting the change to the referee.