The Slovenian was a second-half substitute in the 2-2 draw against Tottenham Hotspur, the point sealed by a last-minute Matthijs de Ligt header.
Sesko himself had a great chance to restore our lead at 1-1, following Bryan Mbeumo's first-half opener, but the 22-year-old was challenged by Micky van de Ven just before shooting.
Not long after that, the striker went down injured and had to be withdrawn, and the Reds carried on a man down, Amorim having already made all of his allowed substitutions.
Speaking in his post-match press conference, the United boss addressed the injury concern.