Shayne Gostisbehere didn’t want to use it as an excuse, but a knee injury suffered when he blocked a shot against Colorado on Oct. 22 lingered for much of the season and reduced his effectiveness.

“Definitely the toughest season I’ve been in personally in my four years,” the Flyers defenseman, who will turn 26 in 10 days, said earlier in the week. “It’s tough, for sure. We’ve been thinking about the season for a while now. I mean, especially when you get knocked out and you have to play four pretty much meaningless games and you’ve just got to go out there and play.”

Gostisbehere’s career has been a roller-coaster ride.

Up: He burst onto the scene during the 2015-16 season and finished second, behind Artemi Panarin, in voting for the Calder Trophy, given to the league’s best rookie. In 64 games, he had 17 goals, 46 points, and a plus-8 rating.

Down: He had just seven goals, 39 points, and a minus-21 rating in his sophomore season.

Up: The Florida native rebounded and had 13 goals and 65 points — fourth among NHL defensemen — and a plus-10 rating in 2017-18.

Down: This season, he had only 37 points (nine goals, 28 assists) and a team-worst minus-21 rating.

“You have to remember, for a lot of these players, this was a different year,” said Chuck Fletcher, who was named the Flyers’ general manager on Dec. 3. “You have a coaching change, a managing change, you’re implementing new systems midstream. Everyone’s wondering what’s the new manager going to do. Is he going to trade everybody? Does he like me, [because] he didn’t bring me in here?”

The knee injury, which Gostisbehere sheepishly revealed this week, played a role in his struggles this season.

“Everyone deals with their injuries,” he said. “… You can’t use them as an excuse. I’m not an excuse guy. I mean, I didn’t have the best season, obviously. I felt I could’ve helped my teammates a lot more, and it’s a grind. It was a mental grind this year. I think a lot of us grew, not only on the ice, but mentally as well.”

His lateral movement, which usually ranks among the NHL’s best, was hindered. That especially affected his zone entries on the power play.

“I got a little better toward the end of the year, but in the middle of the season, I didn’t have the best pop in my step and it was tough for me,” Gostisbehere said. “I mean, you think about it, too.”

Gostisbehere, whose name has surfaced in trade rumors because of his ability and the fact he is signed for four more years with an annual $4.5 million cap hit, started the season on the first pairing with Ivan Provorov. Toward the end of the season, he was frequently on the third pairing, “so obviously, for me, I have to look in the mirror and have a good summer and really bear down and get things going,” he said.

The player they call Ghost was particularly frustrated in the 31-point dip in his plus-minus rating from the previous season.

“I think we made the game really hard for our defensemen with the way we played,” Fletcher said. “We spent way too much time in the defensive zone with the decisions we made up the ice. As a result, you defend too much. … We can do things to make the game much easier for everybody, not just Shayne.”

Gostisbehere plans to train hard in the offseason and “maybe skate a little earlier to get my body right. Just little tweaks here and there with skating and taking care of myself.”

He added: “I want to be a staple point as a defenseman in this league, one of the better ones, not just one who is looked at offensively.”

In his four seasons, Gostisbehere has played for three head coaches. He said he liked playing for talkative interim coach Scott Gordon, a down-to-earth type who was both instructive and demanding. He also knows another coach could be named.

“Whoever the coach will be, I’m going to be a different guy next year,” Gostisbehere said. “I’m going to be definitely different in the way I take my approach to the game. I’m just going to be the best player I can be, whoever the coach is.”