The Liverpool midfielder came out of the match in California needing medical evaluation.
Liverpool's Marko Grujic in action with Chelsea's Bertrand Traore
Liverpool's 1-0 defeat to Chelsea in Pasadena was anything but friendly, despite what the pre-season fixture lists and match programmes may have stated, and it has left one player in hospital according to post-match comments published by Sky Sports.
Serbian Marko Grujic, who joined this summer from Red Star Belgrade and has impressed in the club's other pre-season games, clashed heads with Blues forward Bertrand Traore at the end of the first half, being substituted at half time.
It wasn't the only coming together in the game, even if it was a fairly innocent clash.
Chelsea's Cesc Fabregas looks dejected after getting a red card
Chelsea's Spanish playmaker Cesc Fabregas was another whose challenge against new Liverpool defender Ragnar Klavan became one of the talking points from the match.
The midfielder followed through on the Estonian, earning him a red card - quite an achievement in a friendly.
But it is Liverpool's 20-year-old midfielder that looks to have emerged from the fixture in the worst shape, with concerned Reds boss Jurgen Klopp revealing after the game that Grujic had been sent to hospital for precautionary checks.
"The biggest problem for me in this moment is that Marko Grujic is in hospital, because he can't remember anything," Klopp is quoted as saying by Sky Sports. "That's not too cool.
Liverpool manager Jurgen Klopp
"Hopefully it's not too serious but of course a young boy in this situation is not too cool. Injuries after games like this in pre-season is the biggest problem obviously."
Klopp will be hoping Grujic is able to get back to preparing for the new season as soon as he is healthy, after goals against Fleetwood Town and Huddersfield suggested he could impact the first team in the new campaign.
Liverpool's Marko Grujic celebrates after he scores their first goal against Huddersfield