Varane and Evans were both passed fit to be part of United's squad at Stamford Bridge, with the former starting alongside Harry Maguire, and Evans among the substitutes.
But as the first half approached its conclusion, with the sides locked at 2-2 thanks to goals from Conor Gallagher, Cole Palmer, Alejandro Garnacho and Bruno Fernandes, it became evident that Evans's introduction was imminent.
The Republic of Ireland international replaced Varane for the start of the second half but, after 21 minutes on the pitch, he had to be taken off for Willy Kambwala.
"That doesn't help in such moments if you have to manage the game, [it helps] that there are leaders on the pitch," began Erik, in his post-match press conference.