The Vertical's Adrian Wojnarowski first reported the news Tuesday, adding Noah is expected to need four to six months to rehabilitate and recover. Incidentally, that's the same timetable Noah received after he dislocated his left shoulder in January 2016.
The Knicks noted no decision has been made regarding surgery.
News of Noah's torn rotator cuff comes just over a month after Wojnarowski reported the big man was slated to undergo arthroscopic knee surgery.
It was expected Noah would start serving the suspension at the start of the 2017-18 season, but ESPN.com's Ian Begley reported March 29 that one of the NBA's independent doctors cleared him to play, meaning his suspension started with eight games to go in the 2016-17 campaign.
Noah—who signed a four-year, $72 million contract with the Knicks last summer—averaged 5.0 points, 8.7 rebounds and 0.8 blocks on 49.5 percent shooting in 46 appearances during his first season in the Big Apple.
For more news, rumors and related stories about Joakim Noah, the New York Knicks and the NBA, check out the NBA and Knicks streams on Bleacher Report's app.