Anthony Martial will miss Man Utd's next two games if it's confirmed later that he suffered a concussion in Sunday's defeat to Watford.
The Old Trafford winger appeared groggy following a heavy collision with Hornets defender Daryl Janmaat after 27 minutes.
Martial was able to play on for a further seven minutes but was then involved in the incident which saw Etienne Capoue open the scoring for Walter Mazzarri's side.
The France starlet did appear to be fouled in the build-up to the goal and was immediately substituted feeling dazed and confused.
It's understood Martial still felt uneasy after the final whistle and the rules state a 10-day rest period if a concussion is established.
United boss Jose Mourinho will receive a further update from his medical staff later this morning.
Martial would miss the League Cup tie at Northampton on Wednesday and Saturday's home clash at home to champions Leicester City if the tests do prove conclusive.