HARRISON, N.J. — A topsy-turvy second season in Major League Soccer for Kaku ended with the New York Red Bulls’ 2019 Audi MLS Cup Playoffs Round One defeat to the Philadelphia Union, and a knee injury severe enough that it could involve surgery.

The playmaker was having one of his best games of the year at Talen Energy Stadium, helping set up first-half goals by Josh Sims and Tim Parker. But then he limped off in the 70th minute.

The Union scored eight minutes later to level before winning in extra time, provoking another painful playoff exit for the Red Bulls.

It was especially painful for Kaku, who walked with the assistance of crutches at the club’s season-ending media availability Wednesday at Red Bull Arena.

“At the beginning I thought it was much worse because I felt a sound or a noise,” Kaku said through an interpreter. “Later I realized that it wasn't so bad. I'm not going to be out as long, but it hurt me because I had to leave and couldn't stay on with the team.”

The severity of the injury is still uncertain and Kaku said surgery could be needed. He is certain he’ll miss Paraguay’s international friendly against Venezuela in November’s FIFA window.

“I thought it was much worse, and then the day after the game, I was in a lot of pain,” Kaku said. “And now we're going to try to see if it's worse, if it needs surgery or if it can just heal on its own.”

After a sensational first year in which he bagged six goals and 14 assists, Kaku’s second season with the Red Bulls was tumultuous. It started with preseason transfer rumors and grievances aired through the media by Kaku’s agent when a deal with Liga MX giants Club América wasn’t reached.

That incident, which Kaku said was regrettable, was followed by being left off the gameday roster in March for what Red Bulls coach Chris Armas called “a minor internal issue,” believed to be related to Kaku’s cryptic tweets. And there he was sent off and served an additional two-game suspension for kicking a ball into the stands at Children’s Mercy Park.

It was part of what Kaku describes as a “not great” first three months of a season in which he ended up with five goals and six assists in league play.

“Good decisions were not made with my representative with the club, things were made out to be too big,” Kaku said. “I spoke to Chris, I apologized. And then, things were great. Unfortunately we were unable to put that together in the playoffs.”

In his postseason press conference, Red Bulls sporting director Denis Hamlett lauded Kaku for that reason.

“It took a while, but he came around he understood that, at the end of the day you’re a professional and this is the club you're playing for,” Hamlett said. “I think once he got his mind around that, you can see the success he had on the field.”

Kaku’s singular focus at this moment is on recovery. And being 100% ready, mentally and physically, for the start of preseason. But when the Secondary Transfer Window opens in the summer, “we’ll see what happens,” he said.

“I'm going to try my best to make sure that nobody suffers, nor the team or anyone,” Kaku said. “I’m going to try to do what's best for the team.”