By Andrew Holleran Duke men’s basketball head coach Mike Krzyzewski returned to the sideline on Saturday evening. Earlier this week, Coach K left at halftime of Duke’s game against Wake Forest. The retiring Blue Devils head coach did not come out of the locker room after halftime. On Saturday night, Coach K was back at his usual spot on the bench, for Duke’s win over Florida State on ESPN. Following the game, Coach K revealed what happened at halftime earlier this week. “That’s why I’m retiring,” Krzyzewski said, via The Devil’s Den. “It was basically exhaustion. Nothing else. I feel great.” D…