Tottenham midfielder Rodrigo Bentancur was taken off on a stretcher just six minutes into Wednesday's Carabao Cup semi-final first leg against Liverpool.
The 27-year-old Uruguay international fell while unchallenged as he stretched to head a ball from a corner.
Bentancur was treated on the pitch for around nine minutes and received oxygen before he was replaced by forward Brennan Johnson.
The game at Tottenham Hotspur Stadium was goalless at the time.