West Ham starlet George Earthy was taken to hospital after appearing to be knocked unconscious just three minutes into his Premier League debut.
The 19-year-old required oxygen from medics after landing heavily following an accidental collision with team-mate Edson Alvarez late in the defeat to Fulham.
Doctors immediately sprinted on to the pitch to treat the teenage midfielder and he was removed by stretcher after several minutes of attention.
And West Ham confirmed that Earthy was alert by the time an ambulance transported him to a nearby hospital for further assessment.
Manager David Moyes said: “I’m really disappointed for George. He’s been doing really well in training and with the under 21s, getting much closer to the first team. He had some really nice touches when he came on.
“It was a head knock. He’s awake and gone to hospital for checks. We think he’s OK at the moment.”
A win would have seen West Ham climb to sixth in the table but Moyes rued a lack of control in the centre of the pitch. “What a great position to be in,” he said. “But we gave the ball away in midfield and it opened us up. We were punished.”
Meanwhile, Marco Silva hailed Andreas Pereira after the Fulham midfielder found his “decisive” touch to sink West Ham.
The Brazilian creator raced half the length of London Stadium to celebrate his opening goal with Silva before finishing off a smooth counterattack to seal just a third away league win of the season.
And Fulham’s head coach said of the former Manchester United player: “He knows what I demand from him to arrive in certain areas to be more decisive. He celebrated with me probably because of the way we’ve been demanding more from him in those areas.
“The plan was clear. We told him to be in the pockets and in behind. It is something we've been working on with him to arrive in certain positions.
“Some moments you have to be more decisive, score more goals. But I am really pleased to see him arrive in certain areas. The composure for the first goal was really good to see. It is going to be important for Andreas to be more decisive.”
Join our new WhatsApp community and receive your daily dose of Mirror Football content. We also treat our community members to special offers, promotions, and adverts from us and our partners. If you don't like our community, you can check out any time you like. If you're curious, you can read our Privacy Notice.