The race for the top two spaces in the Championship currently looks to be between four teams - with Hull City, Middlesbrough, Burnley and Brighton & Hove Albion leading the way.
But Karanka has refused to rule out Wednesday, as he has seen shocking twists in the Championship before.
“Sheffield can arrive as this league is crazy,” the Spanish boss said.
“Last season on fixture 34, Derby were at the top and they didn’t make the play-offs, so one thing I have learned in this league is to play every game just thinking about our game.”
Wednesday have been one of the most in-form sides in the Championship since September, and they have progressively climbed up the table.
The Owls made a slow start under Carvalhal’s stewardship, but they have been in formidable form in recent months.
Wednesday have lost just two of their last 13 league matches, to become promotion contenders.
The Owls’ good form has moved them into sixth place in the Championship, but the Yorkshire side are still nine points back from the top two.
Wednesday have also failed to pick up a victory in any of their last three outings, and if they are to make a run for the automatic promotion spaces, they will need to get back to winning ways quickly.