RJ Barrett of the Knicks reacts in the second half...

RJ Barrett of the Knicks reacts in the second half against the Celtics at Madison Square Garden on Oct. 26. Credit: Jim McIsaac

MIAMI — The plans of summer, really the plans that have been in the works since the day that the Knicks decided to trade away Kristaps Porzingis and alter the trajectory of the franchise, have taken a steady procession of body blows.

The coach, David Fizdale, who was supposed to be a part of the three-headed leadership group along with team president Steve Mills and general manager Scott Perry, is gone. The seven free agents who signed on in summer are on the trading block for the next six weeks — free to be dealt now and all aware of the reality that with the season heading toward oblivion, no one is safe.

And even the kids, the player development program touted as the patient core to the reconstruction of the long struggling team, have raised more questions than answers. The two lottery pick holdovers, Frank Ntilikina and Kevin Knox have shown little hints of rising to the draft night expectations the team banked on. Mitchell Robinson remains an intriguing — and raw — project.

That leaves just one player for the Knicks to hang their hopes on — RJ Barrett. And if the 19-year-old rookie, the highest-drafted player for the franchise since Patrick Ewing in 1985, isn’t what they hoped he would be when they made him the No. 3 pick this past summer, then the Knicks are back to square one.

Just what Barrett is or will be remains the mystery that the team still clings to, but one that continues to raise eyebrows around the NBA. One Miami Heat official, before Barrett went out and shot 1-for-10 in a one-sided Knicks loss Friday, said, “I just don’t see it. I don’t see the shooting, the ball handling, the potential.”

The things that Barrett does possess — confidence and maturity — have served him well through the rough stretches in this chaotic rookie season. He has endured a coaching change and his own ups and downs with a calm demeanor and belief in himself.

“Every night’s different,” Barrett said. “You can’t have your best game every night. For me, I’m still a rookie. I’m trying to figure it out. It’s a lot of games. Trying to figure out. Trying to give my all every night. Over the course of a season, every year you have a couple games where you’re not yourself. I just feel like I have to be myself and continue to be aggressive, like [Tuesday’s] game, it’s going to help me. If you worry about the bad games, you’re going to continue to play bad. Just got to move on to the next one.”

Tuesday against Atlanta, Barrett scored a season-high 27 points. He preceded that with a 3-for-12, seven-point performance against Denver and followed it with the ugly outing in Miami. In the last nine games he has had 1-for-10, 1-for-9 and 0-for-9 shooting nights.

“We’re looking at a rookie coming in,” Knicks interim coach Mike Miller said. “He is really mature. Mentally, he is very mature. He’s prepared for this, handles these things. Physically, he puts the work in, handles himself. From teammates to staff, everyone knows what he can do. It’s part of the learning. He sees different things -— the Denver game was different than the Sacramento game. The Sacramento game was different than the Golden State game. He’s learning every time. His adjustment as he’s been playing is outstanding.”

What Barrett will be may still be unknown. But what is known is that he’s the best hope for the franchise and if he doesn’t turn out to be a star then it raises other questions. Not only would it be another failing grade on the current front office, but also make the job less attractive if the Knicks opt to make a change at the top and try to lure an established star executive to remake the team.

Letters of note

When the Knicks parted ways with David Fizdale earlier this month the job when to Miller, but the only coach on the staff with prior head-coaching experience was energetic assistant Kaleb Canales, who had served as an interim in Portland in 2012 after Nate McMillan was dismissed -- becoming the youngest active coach in the league at that time and also the first Mexican-American head coach in the NBA.

But how he got there is a strange story — from serving as an assistant coach at high schools in small towns in Texas to the NBA — and one that Miami Heat head coach Erik Spoelstra is happy to recount.

“It was really incredible,” Spoelstra said. “It’s one of my favorite stories to tell about the video culture. It is a true story. He literally wrote me every week, handwritten notes, about trying to apply for our internship position. It took about three months for me to even recognize that I was getting letters. Finally, I was like, ‘Who is this guy?’ Brought him in for an interview and we ended up hiring [another candidate], but Kaleb interviewed at that time.

“He continued to write me. So at some point, he was applying for a job with the Trail Blazers and I called everybody I knew over there and wrote letters of recommendation for Kaleb Canales, who I barely knew. I felt like it was a brother of mine just because I received so many letters. I’m not the reason he got the job. He’s relentless and he’s been a friend of ours.”

Old soul

Before and after Tuesday’s game against the Hawks at Madison Square Garden Barrett spent time talking with Vince Carter as the 42-year-old future Hall of Famer made his last trip as an active player to the Garden.

“He’s a great guy,” Barrett said. “That’s my OG, a great person, a great person to talk to. He’s always really positive and he’s still killing it. He still kills. He’s not letting up.” Barrett, who wasn’t born when Carter began his career, enjoyed the wisdom, although not so much watching Carter drop 15 points.

“I just try to help all of the young guys and give them as many gems and drops of knowledge to them, if they ask,” Carter said. “I just want to see all these guys succeed. This is a great opportunity. The NBA provides a lot of opportunities for us to fulfill dreams each year. I had a sit with RJ this summer. I know his dad very well. I just told him I’m always available as I’ve told many guys throughout the years. That’s what I enjoy doing, seeing guys succeed.”