Philadelphia ? Boston Red Sox icon Johnny Pesky will have to leave the dugout during games this season because of a major-league rule that limits the number of coaches allowed in uniform.

Red Sox manager Terry Francona said the team was told by the commissioner’s officer it would enforce the rule that limits uniformed personnel in the dugout to players, managers, and six coaches. Francona said the Red Sox received a stern letter from baseball threatening substantial fines.

“They warned us so many times, I think they got tired of it,” he said Friday before Boston’s exhibition game against the Philadelphia Phillies. “I’ve seen the letters in the past.”

Pesky took the news hard when Francona told him this week.

“I sat down with him and talked with him about it, and he was hurt,” Francona said. “I understand. But the rules are what they are.”

“It’s not a new rule. It’s been around for some time,” said Joe Garagiola Jr., a senior vice president in the commissioner’s office. “It is certainly not aimed at any one club or one individual.”