The Celtics had two head coaches present at Saturday morning’s practice. One, of course, was Joe Mazzulla. The other: Mazzulla’s new Patriots counterpart, Mike Vrabel.

Boston Celtics coach Joe Mazzulla has shown up at New England Patriots practices in the past. So he extended an open invitation to newly-hired Patriots head coach Mike Vrabel to do the same at the Celtics’ practice on Saturday. Vrabel reportedly accepted and showed up at the practice.

With two days between games, the Celtics took advantage of a rare opportunity to practice Saturday morning. And that gave Patriots first-year coach Mike Vrabel his first chance to see the team up close since assuming his new post.