Former Knicks guard Ray Williams is battling cancer at Memorial Sloan-Kettering Cancer Center.

“Yeah, it’s colon cancer,’’ Gus Williams, Ray’s older brother who also played in the NBA, told The Post last night. “It’s not looking good. I’m coming up [from Myrtle Beach] to see him [today].’’

Williams, 58, played two stints for the Knicks during his 10-year NBA career. The 6-foot-3 Mount Vernon native played collegiately at Minnesota and was the Knicks’ No. 1 draft pick (No. 10 overall) in 1977 and was their team captain in 1980. He played for five other NBA teams, including the Nets.

Knicks coach Mike Woodson, who played with Williams for two seasons as a Knick, said he visited his former teammate in the hospital last week, as did Knicks assistant coach Darrell Walker, also a former teammate.

“I was just with him last week at the cancer hospital,’’ Woodson said last night after the Knicks’ 87-77 victory over the Pistons.

“Awesome. Physical. Tough. Knew how to play,’’ said Woodson, who also teamed with Williams for the Kansas City Kings. “He was a prototype combo guard because he can play the one, could play two and could guard the three because he was so physical. To see him in the hospital like that, you don’t wish that on anyone.