The forward has been sidelined since the 2-2 draw with Hull City and is now expected to be out for the remainder of 2017-18.
In another cruel twist of fate - rather summing up the Owls’ misfortunes this season - Marco Matias has been ruled out for three weeks with a knee issue, with the news revealed in the wake of his red card being rescinded following last weekend’s dismissal against Birmingham.
On Fletcher, Luhukay, whose side visit Barnsley in a South Yorkshire derby at the weekend, said: “Until the end of the season, he cannot come back to us.
“Steven is with his team now recovering and with the medical (staff) and we must wait a long time for him.
“He will probably not play again this season.”
On the situation with Matias, the Dutchman added: “Marco faces maybe three weeks out of the team. The day after (the sending off) he trained with the players who did not play and had a knee problem.
“We must have three weeks without Marco and maybe be patient that he can maybe come back to the team.”
Fernando Forestieri, out since August 22 with a knee problem, is still receiving treatment abroad and will return to England at the end of this month, confirmed Luhukay.