The 23-year-old has been absent for five weeks with a problem separate from the shin injury that previously troubled him for six months. The club is carrying out further checks at its Carrington training base, according to The Sun, and the full extent of the latest issue remains unclear.
Sources close to Manchester United reportedly fear the forward could be unavailable for as long as four months. Those around Sesko are more hopeful that his absence will not run into February, although there is an expectation that he will miss a significant stretch of the campaign.
The uncertainty leaves manager Michael Carrick with a potential shortage of natural centre-forward options. United did not recruit another striker in the summer after failing to move Joshua Zirkzee on, despite a late enquiry from Everton on transfer deadline day.
Zirkzee has had limited opportunities under Carrick, making only one start in 27 games, while Matheus Cunha has also been used through the middle. Bryan Mbeumo has become a more regular option up front and is joint top of United’s scoring chart this season with four goals. He scored five times while playing centrally for Carrick last term.
United have invested heavily in the position in recent seasons. The club spent a combined £108.5 million on Zirkzee and Rasmus Højlund in successive summers before bringing Sesko to Old Trafford in a deal worth a reported £73.62 million last year. Højlund has since moved to Napoli, with the Italian club obliged to complete a permanent purchase after his loan.
Sesko scored 12 goals in his first campaign at United, and the Sun reports that his contribution helped secure 14 Premier League points. A prolonged absence would therefore be a significant setback as the club considers its options for the January window.
Carrick said on Tuesday that the club hoped to provide a clearer update soon.
“We’re hoping really soon that we’ll have a clear picture,” he said. “I’m not trying to delay it. Hopefully next time we speak, maybe not tomorrow, but by the end of the week, we’ll have something a little bit clearer. There’s a bit of work going on at the moment, so we’ll see what comes out of that.”
Until the medical assessment produces a firmer timeline, United must plan for the possibility that Sesko will be unavailable well beyond the next few fixtures.