BOSTON — David Backes has been in the NHL for a long time, and he takes an immense amount of pride in his game. He knows when he’s earned a day off and when he hasn’t.

That’s why, when most of the Bruins’ top guns were given a holiday Sunday, Backes was on the ice at Warrior Ice Arena in the morning going through an hour’s worth of what looked like fairly tedious skating and puck drills.

Things are going that badly for him right now.

In Backes’ last 12 games, he is minus-11 with just one assist. The last time he was a plus player was Jan. 10 in a win in St. Louis against his old team. His last goal came on Dec. 27 in Columbus, before he missed three games with a concussion. He is minus-5 in his last three games, including minus-2 in Saturday’s maddening, 6-5 loss to the Toronto Maple Leafs at the Garden.

Skating on his line with Frank Vatrano (another attendee Sunday) and David Krejci, Backes coughed up the puck at his blue line, which led to the Maple Leafs’ first goal.

And so Backes decided that a mental and physical break was not what he needed.

“There have certainly been lulls in my game at times and you try to make them as short and brief as possible,” Backes said, “but I think the saving grace a lot of the other times was that the team was winning and I was finding ways to contribute, with screens in front and pucks were going by you and you were able to celebrate some goals. But we haven’t produced much secondary scoring at all. One of the reasons I’m here today is to get better, put some work in. I take full responsibility for the first goal against Toronto. We want to be a positive contributor to this team and help us win games. That’s what our focus is on and needs to be, starting Thursday (against San Jose.). We’ve had long enough without contributing.

“That one line with (Patrice Bergeron, Brad Marchand, David Pastrnak) has put everyone on their backs. We need secondary help for them and that’s got to come from guys like Krech and I and all the way down the lineup.”

Backes, a natural center, was on board with being a high-priced utility man when he signed a five-year, $30 million deal with the Bruins last summer. If the situation called for him to be a winger, then he’d play on a wing. If the Bruins needed a center, that’s what he’d be.

But lately, he hasn’t looked all that comfortable at either position. He’s played mostly as Krejci’s right winger, and was minus-3 in his one game at center during this rough patch, at Detroit on Jan. 18 with Ryan Spooner and Austin Czarnik on either side.

Backes feels his struggles have nothing to do with whatever his role.

“It doesn’t matter where I’m playing,” he said. “I just need to be a better player on the ice and I’ll help wherever I’m playing, whoever I’m playing with, and be productive and help us win games. If that’s on the right with Krech, or that’s at center or that’s moving all around, if I’m winning battles and doing what I do well when I’m playing well, then we’re going to be a better team. That’s on me and I own that.”

When he signed in the summer, it would have been reasonable to be concerned about the last couple of years of the deal. Having always preferred to go through the brick wall than around it, Backes, 32, has some hard miles on his body. But now, age cannot fully explain the difference between Backes today and the player who was so effective in the playoffs for the Blues last spring, or the guy who had two goals and an assist, and was plus-5, on opening night in Columbus.

But a crisis of confidence can hit the most accomplished of players. And right now, his thought process is slowing him down a lot more than his legs.

“I don’t know if it’s confidence, or not feeling it at times and not having the assurance that when you have (the puck) that something great’s going to happen,” Backes said. “That’s more of a mental thing that I need to wrap my head around, that every time I touch it something great’s going to happen, not letting something poor happen.

“I’m fighting it a little bit, no question, and that’s why I’m out there today, to hopefully make that little black puck my friend.”