It actually could happen but for now Ward is retired. The Ward who fought two fights against Kovalev vs. the Canelo who fought Kovalev. Who takes it?
Even though it was a good performance by Canelo Alvarez, defeating Sergey Kovalov, Andre Ward would defeat him by unanimous decision. Andre is much too schooled and has enormous skill to lose to power punching Canelo. Ward by unanimous decision.
Ward by UD if there's any unbought judges. Canelo by robbery in Vegas. Ward would fight his usual spoiling, mauling fight, and Canelo would be comprehensively out-generalled. Canelo might well beat a "comeback" Ward today, however. Old and semi-retired fighters excite him.