How Jrue Holiday is finding new ways to “raise hell” on defense for the Celtics

BOSTON — What is Jrue Holiday’s position? He’s a combo guard one quarter, and a big man the next. The Celtics want to be versatile, and he can do pretty much everything on both ends of the floor well. But in his return from an ankle sprain Monday night, Joe Mazzulla had a new position for him: free safety. “Tonight it was Jrue’s turn to like — we didn’t start him on (Nikola) Vučević, we didn’t start him on (DeMar) DeRozan. We kind of put him on another player to where he could be a free safety and go make plays and raise hell in our shift activity,” Joe Mazzulla said. “So he kind of tonight was the catalyst towards…