Pierce had been excused from the team for personal reasons and did not play in Monday's game in Minnesota. Instead he returned to Boston after Sunday's loss in New York and, on Tuesday at 8:21 p.m., wife Julie, and the couple's two daughters, welcomed the baby boy.
Pierce revealed the new addition as part of a postgame interview with Boston sports radio WEEI.
Back on the court on Wednesday night, Pierce finished with 17 points, five assists and three rebounds. He struggled with his shot -- 5-of-14 overall, while missing five of the six 3-pointers he attempted -- but was a team-best plus-8 in plus/minus as the Celtics topped the Pistons 98-93 at TD Garden.
Pierce has been nursing a sore right ankle that likely would have kept him out of Monday's game in Minnesota anyways (Celtics coach Doc Rivers had said Sunday he planned to rest Pierce that day). Pierce suggested he might sit out practice on Thursday in order to get some additional rest.
And, as every new dad knows, you take your rest where you can get it with a newborn.