Diego Costa could return to action for the final match of Chelsea’s tour of the United States against AC Milan on Wednesday, even if his future at Stamford Bridge remains shrouded in mystery. The Spain striker has not featured in Chelsea’s first two matches in the U.S. – a 1-0 win over Liverpool and 3-2 defeat to Real Madrid – after suffering with a back injury. But he is expected to be declared fit for a match that will be the first event held at the new 66,000-capacity U.S. Bank Stadium in Minneapolis.