By Joseph Salvador Pending a physical, Mayfield is joining the Panthers and the Cardinals quarterback seemed thrilled for him. Kyler Murray and Baker Mayfield are not only both NFL quarterbacks who played at Oklahoma, but they’re close friends. So when the Panthers announced that they made a trade for the former Browns signal-caller, his friend just couldn’t contain himself. “WORK OUT!” Murray said in a Tweet on Wednesday. Surely the Cardinals quarterback is thrilled that his friend gets a new start with a new team and it sounds like he’s ready to get some work in. The deal is still pending a …