Thursday, November 22, 2012
When a manager, player, coach or trainer is ejected from a game, he shall leave the field immediately and take no further part in that game. He shall remain in the club house or change to street clothes and either leave the park or take a seat in the grandstand well removed from the vicinity of his team’s bench or bullpen.
Rule 4.07 Comment: If a manager, coach or player is under suspension he may not be in the dugout or press box during the course of a game.
When an individual is ejected from the game, he may not stand in the runway between the dugout and clubhouse. Umpires are directed to report this type of violation to the league officials and not further delay the game. [PBUCUM]
In this video the manager is ejected, but sneaks back into the dugout.
The rules do not prohibit "communication" from an ejected manager. [BRD]