United got its season up and running with a 4-0 Premier League win over QPR last weekend – van Gaal's first competitive victory since moving into the hot seat at Old Trafford – and it will hope to continue that form against another newly-promoted side at the King Power Stadium.
Such has been the turmoil at the start of van Gaal's reign that only four players – Rooney, David de Gea, Tyler Blackett and Juan Mata – have started all four of United's Premier League matches so far.
After it added the attacking talent of Angel Di Maria and Radamel Falcao during the recent transfer window, much has been made of how van Gaal will accommodate all of his forwards.

"There are always players you put in a team. My captain shall always play and normally the goalkeeper, so it's not a surprise," van Gaal said.The Dutchman has denied it will result in a straight fight between Falcao and Robin van Persie to play alongside Rooney but he has also suggested that other than goalkeeper de Gea, Rooney will always play.
"Maybe it's a surprise Blackett has played all the games but he has played well and Mata is a very good player.
"I don't think any player is fixed. Only the captain has more privileges but no other player has privileges I think. Every player knows that because you see how I manage my teams."
Van Gaal has indicated he will stick with the 4-3-3 shape he deployed against QPR and that the formation will benefit forward Adnan Januzaj, who has not yet started in the Premier League this season.
Van Gaal has regularly bemoaned United's lengthy injury list but defender Chris Smalling, who has been struggling with a groin problem, is now available again.
Michael Carrick, Ashley Young, Phil Jones, Marouane Fellaini and James Wilson are among those still missing for United, which has won its past 10 matches against Leicester City.
Foxes manager Nigel Pearson believes United has its "swagger" back after a difficult time under David Moyes that saw the Scot sacked less than one season after he replaced retired compatriot Alex Ferguson, British football's most successful boss, at Old Trafford.
New manager van Gaal has added plenty of attacking threat, including Di Maria and Falcao, and his opposite number is under no illusions as to the size of the task facing his side on Sunday.
"It's potentially our most glamorous fixture at the King Power," Pearson said. "It's a fixture that a lot of people look for.
"Manchester United have been the most dominant domestic club. They are a world brand and have made their recruitment intentions quite clear.
"United look like they have a swagger back, they have added quality.
"When you have someone in charge for as long as Sir Alex Ferguson, the transition period will never be easy.
"They have been a huge presence within the English game for a long time. I'm sure they will reignite that at some point."
Pearson has just one injury to his first team with Matt Upson ruled out.