LAS VEGAS — Jordan Walsh called his ejection Monday against the Heat a “rookie mistake.” His coach, Joe Mazzulla, watching from high in the bleachers of Cox Pavilion with his family, texted his young swingman and said he “loved” the fire.

LAS VEGAS — Jordan Walsh admitted it was a “dumb decision” made partly because he forgot he had picked up a technical foul just moments before. But regardless, he owned up to his ejection from the Celtics’ Summer League loss to the Heat on Monday.