It was Celtics coach Joe Mazzulla, who stopped by to spend some time on the sidelines. Mazzulla has been a guest at previous Patriots practices under Bill Belichick and Jerod Mayo. He grew up a Patriots fan in nearby Johnston, RI and enjoys learning from other coaches.

Mike Vrabel had a special guest in Foxboro for the seventh day of Patriots training camp on Wednesday: Boston Celtics head coach Joe Mazzulla.

Mike Vrabel is unique in that way. He puts on a pad and engages with the linemen. He also enjoys trash-talking with the players. Williams, who signed a $104 million free agent deal, is enjoying all that Vrabel brings to the table as a head coach.