The school released a statement from coach Chris Collins, who said Turner will "focus on aspects of his life other than basketball" and that his status with the program will be re-evaluated "when the time is appropriate."
Teddy Greenstein of the Chicago Tribune cited sources in writing that Turner may never make it back after "not meshing" with Collins and his new staff.
As of Tuesday afternoon, Turner was no longer listed on the Wildcats' official roster.
Turner appeared in all 32 games as a redshirt freshman last season, averaging 1.9 points and 2.0 rebounds per game in Bill Carmody's last season as the Northwestern coach.
Rodger Sherman at Sippin' on Purple wrote on the roster move as a mostly positive step forward in Collins' early tenure at Northwestern.
If anything, I think Turner's absence forces Northwestern into a good situation. NU will have solid talent at the 1-4 spots, but often played Turner more from a "hey, we should be playing a center now, right?" perspective even though he was outmatched defensively and put a hitch in NU's offense.