Knicks star Amar’e Stoudemire needs surgery on his right knee and is expected to miss six weeks, a stunning blow to the team as it chases the Atlantic Division title. Stoudemire, who had been playing well off the bench, will have the procedure to remove tissue within the week, the Knicks said Saturday before their game against the Jazz. Stoudemire missed the first 30 games after having the same surgery, called a debridement, on his left knee during preseason. He returned on New Year’s Day and has averaged 14.2 points in 29 games. The Stoudemire news was a surprise, since there was no indication there had been any problem with his surgically repaired knees until Saturday morning. Stoudemire didn’t take part in the shootaround, and had an MRI later in the day . . . The Mavericks waived guard Dominique Jones, a former first-round draft choice who was in his third season with Dallas.