The France international was originally named in the starting line-up for the game at Old Trafford and was set to partner captain Harry Maguire in central defence for the fifth consecutive match.
However, around 40 minutes before the 20:15 GMT kick-off, it was announced that Varane was ill, with Victor Lindelof taking his position in the XI and Tom Heaton promoted to the substitutes' bench.
No further reasoning was provided prior to the beginning of the game, but after United had secured the three points thanks to goals from Cristiano Ronaldo and Bruno Fernandes, the interim manager provided an update on our no.