Carson, linked today with a big-money switch to Portsmouth, played for The Owls at the back end of last season and was excellent.
Sturrock has waited and waited for the England goalkeeper to become available and has missed out on other transfer targets as a result.
It is believed that The Reds want a big fee for the player so he can come to Hillsborough on loan and for Wednesday to pay his entire wages.
Sturrock told the club's official site: "It's not looking as if we're going to get Scott but until I get a certain 'no' I'm going to keep going down that road.
"We've lost a couple (of options) because of the wait. Plan A has always been Scott, plan B has been scuppered because of waiting on Scott and now we are on plan C."