Kelechi Iheanacho scored his second brace in the month of January while Wilfred Ndidi scored deep in stoppage time to help Leicester City thrash Petersbrough United 5-1 in the FA Cup fourth round. "If you sit back against Premier League teams they will pick you off and beat you easily".
Meanwhile, the Posh are without Gwion Edwards due to injury whilst new signing George Cooper and Joe Ward are both cup-tied.
However, top scorer Jack Marriott is hoping to overcome a knock to be involved. Captain Wes Morgan (hamstring) remains out, though.
Chelsea face Newcastle in another all-Premier League clash on Sunday when league leaders Manchester City continue their bid for an unprecedented "quadruple" of major trophies (Premier League, FA Cup, League Cup and Champions League) away to second-tier Cardiff.
The Foxes have progressed from six of their last seven fourth-round ties against lower-league opposition, with their only defeat coming at the hands of West Brom in 2001/02 (0-1).More news: James Franco Removed From Vanity Fair Hollywood Cover
But they could not make any further inroads into Leicester's lead, which was extended in the 87th minute through Diabate, who looked to be in an offside position when Demarai Gray's shot was palmed into his path, but the flag stayed down, allowing the forward to power the ball into the roof of the net.
Iheanacho, who now has nine goals in five FA Cup starts in his career, was taken off in the 80th minute.
Vardy replied to Penny's comments by saying: "It will be interesting but we will wait and see as there haven't been that many people who can catch me".
"I have been waiting for an opportunity to take my chance and this was it".