Celtic still have Cameron Carter-Vickers and Alistair Johnston involved at Copa America while some of their players trickle back in for pre-season. Johnston’s Canada have made a strong start to Group A, competing in a 2-0 defeat to Argentina before claiming a 1-0 victory over Peru earlier this week. Nevertheless, it was the United States’ turn last night to try and claim some points; however, they fell to a surprise 2-1 defeat against Panama on a night where former Celtic man Timothy Weah was sent off for striking his opponent in the back of the head. Carter-Vickers came off the bench at half-…