The 22-year-old suffered an upper-body injury Jan. 4. He was initially projected to return in mid-February, but that's no longer the case.
"He didn't have a setback, but he just had an appointment yesterday. We're looking at another week or two," head coach Paul Maurice said Wednesday. "He was getting close to the end of the window and wasn't feeling a whole lot better. Then we had it checked again. It's going to be longer than we thought."
Maurice added that it could be "one-to-three weeks before he can play."
The Jets have gone 11-5-1 in Ehlers' absence to remain atop the Central Division.
Before being hurt, Ehlers had recorded 27 points in 40 games.