Despite the Knicks’ brutal record and growing input of Phil Jackson, who reversed the head coach’s offense, Jeff Hornacek’s job is safe, according to an NBA source.

In his three years as team president, Jackson has had four head coaches and, though this club was built to win now, there’s no plan for a fifth head coach this summer. The Knicks fell out of the playoff race in early March and take a pitiful 27-41 record — the league’s seventh-worst — into Thursday’s Garden rematch against the Nets.

In the week leading into the All-Star break, Jackson encouraged Hornacek to re-emphasize the triangle offense and step back from the coach’s hybrid attack because of the team’s sputtering. It was a clear indicator of Jackson’s dissatisfaction with Hornacek’s “early offense.” Even Kristaps Porzingis classified the offense’s travails as causing “confusion.’’

When Jackson fired Derek Fisher in February 2016, during the coach’s second season, it was not because of a poor win-loss record. Sources insist Fisher was dismissed because of his lack of communication with Jackson, failing to respond to Jackson’s emails promptly and a passive-aggressive resistance to Jackson being involved with coaching aspects.

Hornacek, according to an NBA source, gets high grades on both counts — maintaining a strong rapport with Jackson and associate head coach Kurt Rambis, Jackson’s longtime compatriot.

Jackson’s coaching role has grown in recent weeks because of the collapse. He staged a triangle clinic a week ago for the guards. On Wednesday, Jackson was on the court during practice, talking animatedly to Rambis, the defensive coordinator, while going over positioning and footwork.

If Jackson should have promoted then-interim Rambis as coach last spring, it’s too late now. Though owner James Dolan has given Jackson carte blanche, Jackson would look awful if he bagged Hornacek.

“Phil can’t afford to fire [Hornacek] and bring in a new coach,’’ said another NBA source, who has spoken to Jackson.

Hornacek said he’s not worried about being the fall guy.

“No, we’re all going through this,’’ Hornacek said after Wednesday’s practice. “Every single guy, every single coach, every part of management is to blame. We’re all in it together. There’s no other talk of anything. We’re trying to grow from this.’’

Asked if he felt Jackson stepped on his toes, Hornacek said, “We talk about stuff all the time. When he comes out and demonstrates for guys, he’s so used to being out on the court. It’s fun for him to do. Guys getting another look at it from a guy who’s run it for years and years.’’

Hornacek had no history with the triangle, but now touts it like a good company man. Hornacek picked his own coaching staff and brought in Jerry Sichting, Corey Gaines and Howard Eisley, none of whom knew the triangle from a rhombus.

The coaching staff may get new blood in the offseason with, say, triangle guru Jim Cleamons, who was not retained, or Brian Shaw, hired by Luke Walton for his Lakers staff.

Carmelo Anthony also has given off signals of discord, referencing the lack of adjustments made during games. Kyle O’Quinn, in the doghouse after not playing Tuesday against Indiana, stormed away from Rambis during a timeout while Rambis lectured him about a defensive faux pas.

Feeling he took some things for granted regarding defensive fundamentals, Hornacek said next training camp he will do things differently. The coach also acknowledged his hybrid offense may have baffled returning players who were used to the same-old triangle.

“It ended up being confusion in terms of getting some of the guys here last year, [they] were confused on some of the things we mixed in,’’ Hornacek said. “We’ll look at a lot of different things. Go back, step 1: a lot of footwork and basic fundamental stuff as the season goes on you notice. Next year when we go into it, it’ll be more to that stuff before you even touch a basketball.

“A lot of times things are taken for granted on both ends — crossing of the feet. It’s the old high school thing. You don’t cross your feet. The more tape you watch, they do it occasionally. It’s creating that habit so they do it 98 percent of time and not one time this way, one time that way.”