All star trade

There was some speculation about this situation with carmelo when he was on the trading block two years ago.

If a player gets traded, he is added as a 13th player to his new conference's team, coming off the bench (even if he was the leading vote-getter). The other conference adds a replacement, so the player's new conference has 13 andhis old conference has 12. Por ejemplo, if Lebron got traded to the Phoenix Suns, Lebron would be moved to coming off the bench for the West, who would have 13, and a replacement player would be added to the East and someone would take Lebron's place as starter.

This happened before when Kidd was traded from the Nets to Mavs around the break. Not exactly sure if the trade was official yet but I think it was and he ended up starting for the East team while playing his next game with the Mavs.