Owls striker Gary Hooper faces 10 weeks on the sidelines after undergoing groin surgery, The Star understands.
Hooper, out of contract at the end of the season, posted an injury update on his Instagram page.
Tottenham Hotspur's midfielder Victor Wanyama, who alongside Hooper for two years at Scottish club Celtic, was among those to wish Hooper well in his recovery.
He wrote: "Get well soon bro @hoop588."
The 30-year-old has not featured at senior level since Wednesday's away victory to Nottingham Forest last December.
Hopes were raised that Hooper was edging closer to a first-team comeback when he completed 45 minutes of an Under-23s match against Colchester United on September 10.
But that proved a false dawn, prompting manager Jos Luhukay to admit last month that Hooper and Kieran Lee were unlikely to play again this calendar year.
Luhukay said: "I think these two players will not play again for us this year. They have had treatment in the last weeks and months but they are not on the field.
"They are not training with the sports science staff. It is only physio work they are doing. Kieran has been out over a year. Gary has been out since December.
"Hopefully Gary and Kieran will come back to the team in January."
Meanwhile, Fernando Forestieri is back in full training, having recently received treatment in Spain for a hamstring injury. The talented forward picked up the knock in the Owls' 2-1 triumph at Bristol City and has missed the last three matches.
Saturday's home encounter with fourth-placed Norwich City could come too soon for Forestieri, who has notched three goals in 10 outings this season.
Steven Fletcher is set to spearhead the line again following his impressive contribution in the 3-1 defeat at Birmingham City last weekend. Lucas Joao is vying with Atdhe Nuhiu to partner Fletcher in attack.