Returning from World Cup action with England, the two Foxes' stars helped their nation reach the semi-final stage in Russia. With a lack of rest and recuperation, it could be seen as a risk to start both players against Manchester United.
BBC Sport suggest that Puel still is unsure on risking the duo, fearing that burnout could result in some problematic injuries. With just four days training each, it may be a better idea to integrate those who've made an impact in preseason.
With Jonny Evans, James Maddison and Rachid Ghezzal all in line to make their debuts, it is a season of excitement for the Leicester fans. Bringing in Caglar Soyuncu from Freiburg and Dinamo Zagreb's Filip Benkovic on deadline day, the Foxes now have plenty of defensive cover.
If Vardy is to be rested, young Nigerian Kelechi Iheanacho will likely play. Signed from Manchester City for a pricey £25m, the Leicester faithful are wishing to see more from their young star.
With Manchester United disappointing supporters with no transfers yesterday, the mood in Salford could turn sour if the Red Devils don't make a strong start. With stars Paul Pogba and Romelu Lukaku late returners from the World Cup, a large amount of onus will fall on Alexis Sanchez and Juan Mata.
Injuries to Antonio Valencia, Marcos Rojo, Diogo Dalot, Ander Herrera and Nemanja Matic leave Manchester United in trouble. With youngsters Scott McTominay and Anders Pereira potential midfield starters, Leicester may sense opportunity for a positive result.
Appearing in every match over the summer, Maguire had a great tournament and was a stand out for the Three Lions. Rumours had swirled about him moving to Old Trafford, but the centre-back is staying put.
Vardy signed a new four-year contract yesterday, and is raring to go with Leicester. An absolute stalwart in the incredible 2015/16 season, the forward will aim to replicate such scoring form once again.