Manchester United left-back Luke Shaw will visit a specialist after suffering damage to a ligament in his foot, Sky sources understand.
Shaw limped off nine minutes into United's 1-1 Premier League draw with Swansea on Sunday and the damage to his foot was shown up in a scan on Monday.
The England international is coming to the end of a frustrating season, having made only 20 appearances after having fallen out of Jose Mourinho's plans.
Shaw had worked his way back into United's first team in recent weeks and was looking for a positive end to the season to secure a regular place for the 2017-18 campaign.
The 21-year-old is one of a number of United players under an injury cloud towards the end of what, thanks to their run to the Europa League semi-finals, has been a busy season.
Ivory Coast defender Eric Bailly was also injured against the Swans, his twisted ankle leaving Mourinho even shorter of centre-back options.
Bailly has forged a successful partnership with Daley Blind but his injury potentially leaves United with no senior central defenders for the first leg of their Europa League semi-final with Celta Vigo.
Mourinho said on Monday that Matteo Darmian could fill in at the heart of defence, as could Michael Carrick or youngster Axel Tuanzebe.
Zlatan Ibrahimovic and Marcos Rojo are both sidelined by serious knee injuries, Paul Pogba could return soon from a hamstring issue, while defenders Phil Jones (foot) and Chris Smalling (knee) remain on the injured list.