WASHINGTON — When Knicks coach David Fizdale found out recently the club would have to stay over in D.C. after its first preseason game because of Westchester Airport construction, he sought to make the most of the experience.

On Tuesday, the Knicks, who opened the preseason Monday with a win over the Wizards, visited nearby Walter Reed National Military Medical Center, which provides medical assistance to 150,000 soldiers.

“I felt, let’s not waste this opportunity,” Fizdale said. “I just felt to visit those soldiers, it does something for the soldiers. For our team, it gives them perspective and make you appreciate what you have. Hopefully it gives them an understanding what service is, selflessness is. What I’m asking isn’t anything [compared] to what these guys have given. I know our guys are looking forward to it and it has an impact.”

The visit will have a profound effect on 2018 lottery pick Kevin Knox, who has had a handful of family members serve in the military. Knox’s uncle, Raymond Estelle, was killed in Afghanistan by friendly fire when Knox was in middle school.

“It means a lot to me to see the soldiers,” Knox said. “My uncle, it was definitely tough for my family, and we got through it. Every time it’s a Military Appreciation Night it’s always a big night for me because of (my uncle) and my family history with the military.”

Julius Randle said he believes the visit will be meaningful.

“We talk about sacrificing in the NBA,” Randle said. “Those guys made the ultimate sacrifice. A lot of things happened to them and they’re still 100 percent committed to what they’re doing. I’m excited, and it’s a good experience for all of us.”

The Knicks have not gone away for training camp since Phil Jackson’s 2016-17 team, which finished a three-year training-camp stint at West Point. This is the third straight year they’ve stayed put at their Tarrytown headquarters.

Fizdale said players from the Heat title teams on which he was an assistant coach visited the base hospital after their White House visits, but the coaching staff did not.

“Perspective,” Fizdale added of the visit to Walter Reed. “Some of those guys are younger than (our) guys. The stuff they sacrificed and lived through, I’m hoping that gives our guys perspective and gratitude for where they are.”

Knicks president Steve Mills and GM Scott Perry signed autographs and took pictures with vets. Randle, Knox, Dennis Smith Jr., Marcus Morris, Wayne Ellington and Taj Gibson visited wounded soldiers in their rooms.