Cooke was taken off after an hour of the Hillsborough clash, following a collision with Diamonds keeper Billy Turley, but x-rays have revealed no break to his leg.
The Owls are hopeful that Cooke will be fit to return to action in the next fortnight, although he will definitely miss tonight's clash with Plymouth Argyle.
The 27-year-old wideman has been a virtual ever-present after returning to the club in the summer from Grimsby Town on a free transfer.
He had previously been on loan with the Owls during the 2000-01 season, while with Manchester City.