The Celtics have a slight issue when Kyrie Irving is on the bench

Kyrie Irving had a plus/minus of zero in the Celtics’ 109-105 loss to the Warriors on Saturday. That means had he played all 48 minutes at the same rate he played his 36, Golden State and Boston would have headed to overtime.

But Irving didn’t play all 48 minutes because he’s not made of the same things robots are. In fact, his 36 minutes should have been enough: he scored 37 points on 13-of-18 shooting and 5-of-6 on threes.

But in the moments Irving went to the bench for Boston — much like the moments Russell Westbrook went to the bench for the Thunder last season — the Celtics offense struggled. Terry Rozier was minus-19 in 24 minutes on the floor. Despite the All-Star guard’s outstanding performance, the Warriors, as they often prove, were just too much to overcome.

Irving bet on himself when he requested a trade from Cleveland, and landing in Boston was the best possible outcome. But once Gordon Hayward went down with an ankle injury in the opening seconds of the very first game, the brunt of the offense shifted back onto his shoulders.

Irving has largely answered the bell. He’s averaging 24.5 points on 48 percent shooting from the field and 39 percent shooting from three. He’s one of the league’s 10 best fourth-quarter scorers and has been a beast in the clutch. But the problem against better teams will be when he goes to the bench.

Boston is 10.5 points worse per 100 possessions on offense when Irving is on the bench. In money time, also known as the post-season, the Celtics will need an answer for that.

That’s not to say Rozier is a scrub; not by a long shot. After all, the heavily contested shot he hit with just a few seconds left against the Warriors to slice the lead to one is proof he can hoop.

But two of the Celtics’ starters (Jaylen Brown and Jayson Tatum), as talented as they are, are still early into their NBA careers. Aron Baynes is a solid big man but doesn’t move the needle much, and Al Horford is an All-Star. It’s almost as if Boston is missing someone.

That someone is Hayward, who could very well return for Boston at the end of the regular season, which would give him enough time to ease back into the lineup for the playoffs. In December, he had progressed to the point where he was out of his walking boot. Now, he’s taking part in warmups and shooting non-jumping shots.

Irving has proven he can lead, and the Celtics have the Eastern Conference’s best record in large part because of his play. His supporting cast has also stepped up, but when Kyrie goes to the bench, Boston becomes a different team.

We saw it in the Celtics’ loss to the Warriors on Saturday. If they want to eventually dethrone Golden State, Boston will have to figure out what to do with Irving off the floor.