Rangers replaced Burnley on top of the pile last weekend after the Clarets drew 1-1 with Leicester at the King Power Stadium.
At the start of December it was the Foxes in first place but they have lost three of their last four games, most recently to Manchester City in the Capital One Cup quarter-finals on Tuesday.
Leicester have conceded nine goals over the four games and on-loan Arsenal defender Ignasi Miquel believes that is the area that is letting them down.
He said of the QPR clash in the Leicester Mercury: "It's massive. That game, if we win, we just bounce back.
"It's been in the background for us and we now want to get back on Saturday and win.
"I think we definitely need to improve defensively at QPR. We conceded three goals so it's something we have to improve at.
"Saturday's game is as big as (the City) one. They are top of the league and we need to hit them and get back into the league."
QPR have taken seven points from their last three games, keeping clean sheets in all of them to move two points ahead of Burnley.
Former Liverpool, Chelsea and Arsenal midfielder Yossi Benayoun joined Rangers last week and could be in line for a debut.
He is convinced Harry Redknapp's side are on course for an immediate return to the Barclays Premier League.
The Israeli told www.qpr.co.uk: "The squad here is very strong and is definitely good enough for the Premier League. It is where this club should be.
"There is only one target here - to win promotion in May.
"I want to help the squad with my experience, and I believe in my ability.
"There are a lot of games and I want to come in and work hard for the club, just like everyone here is already working hard.
"I want to do all I can for this club to achieve promotion."
Second-placed Burnley take on Blackpool, who have slid out of the promotion places after three defeats in a row.
Form team Derby will look to make it seven victories in succession against Doncaster while fifth-placed Reading meet Wigan, who were ahead when their match with Sheffield Wednesday was called off because of a waterlogged pitch on Wednesday.
Leeds in sixth contest a Yorkshire derby against Barnsley, with Nottingham Forest travelling to Birmingham and Brighton meeting Huddersfield.
Giuseppe Sannino's first match as head coach of Watford comes against Ipswich, where the Italian will attempt to halt a run of nine games without a win.
Also on Saturday, Charlton travel to Bolton, Sheffield Wednesday host Bournemouth, Blackburn visit Yeovil and Millwall meet Middlesbrough.