Barnsley, four points from safety at the bottom of the npower Championship, have been unsuccessful in their approach for two new managers - Sean O'Driscoll and Terry Butcher - since sacking Keith Hill after the home defeat to Blackburn on December 29.
The Reds have won only one of their last 15 league games, but beat Burnley in the third round of the FA Cup last week in caretaker-boss David Flitcroft's second game in charge.
Warnock said: "I always think the games against the teams at the bottom end of the division are far harder because everybody expects you to do things.
"I know how difficult it is at Barnsley. They actually gave us a lesson at Elland Road, they battered us for half an hour. How they didn't score I'll never know. That's the fine line in management I suppose and two or three of the other games I've seen them play, they've been very unfortunate.
"And the way they play, they're really solid and hard and I'm sure with the Yorkshire crowd behind them, they're one of my old clubs and I really enjoyed myself at Barnsley, so it's an exciting atmosphere and I'm looking forward to it."
Barnsley have won their last three home games against Leeds, including a 4-1 trouncing on New Year's Eve in 2011.
Warnock added: "Reading the reports from previous games there, it's not a happy hunting ground. I think last year, from what I've read, it was probably the worst display the fans had seen a Leeds team play, so we've got to try and give them something better than that.
"The minimum we've got to give is 100 per cent. It's always difficult at Barnsley, where ever they are in the league. Their performances haven't been too bad, that's why I thought Keith was a little bit unlucky really."