Manchester United striker Javier Hernandez was kept in hospital overnight after suffering from concussion.
The forward sustained the injury during a training session at the Red Bull Arena in New York City on Tuesday.
United's medical staff sent the 23-year-old to hospital, where doctors decided he would stay overnight.
The club are currently in the USA on a pre-season tour where they will next face an MLS All-Stars side featuring Thierry Henry and former Manchester United midfielder David Beckham.