Manchester United forward Anthony Elanga appeared to be struck by an object from the Elland Road crowd during celebrations for the Red Devils’ third goal.
The 19-year-old dropped to the floor holding his head in the aftermath of Fred’s goal in front of the Norman Hunter South Stand.
The object appeared to be a coin thrown by one of the home supporters as the away side ran towards the away end to celebrate.
Elanga was given medical attention before play was allowed to resume by Paul Tierney but did not need to be substituted.
The young Swedish forward went on to score the last of the visitors’ goals as they inflicted a 4-2 defeat on Marcelo Bielsa’s side.
The FA will likely investigate the situation and, if they find sufficient evidence that it was an object thrown by a Leeds fan, it won’t be the first time this season such an incident has happened at Elland Road this season.
In earlier fixtures this term against Brentford and Burnley, Sergi Canos and Matt Lowton were both similarly struck by objects that entered the field of play.
Leeds are also likely to investigate the incident and will punish the fans involved if it is proven that the object was thrown by a home supporter.