Indians manager Terry Francona expected to see Oliver Perez run out of the bullpen. Pitching coach Carl Willis made the call for Dan Otero instead.
The mixup was a miserable one for the AL Central leaders.
Joey Votto hit a go-ahead, three-run double off Otero in the ninth inning as Cincinnati scored seven times with two outs, overcoming a gem by Trevor Bauer to beat Cleveland 7-4 on Tuesday night.
Francona instructed Willis to have "O-P" warm up, referring to Oliver Perez, with the bases loaded and a 4-3 lead with closer Cody Allen struggling. Willis misunderstood the message, believing he had used Otero's nickname of "O-T."