Ryan Mason has undergone an emergency operation following his horror clash with Chelsea defender Gary Cahill.
The Hull midfielder, 25, was rushed to hospital after a sickening aerial collision that left him with a fractured skull.
Mason was treated for nine minutes on the pitch by medics after the incident before being taken off on a stretcher in a neck brace while receiving oxygen.
A Hull statement said on Sunday night: "The club can confirm that Ryan Mason sustained a skull fracture in our fixture at Chelsea this afternoon.
"He was taken to St Mary’s Hospital where he has undergone surgery.
"Ryan is in a stable condition and is expected to remain in hospital for the next few days.
"Everyone at the Club would like to express their sincere thanks for the excellent and swift care given to Ryan by both the Accident and Emergency department and Neurosurgery Unit at St Mary’s Hospital."
Cahill, who was able to continue the match, later revealed his concern for former Spurs star Mason.
Speaking before the full extent of his injuries were known, he said: “We smashed heads, there was a massive impact and I know he went off. I wish him all the best.”
Manager Marco Silva said immediately after the game: "I imagine in this moment that he will stay in hospital. I hope nothing special, nothing serious, but we'll see.
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"I don't know (if he is awake). He doctor told me he was in the hospital and we await news.”
Referee Neil Swarbrick had stopped play as medics rushed on to the field to attend to Mason, giving him oxygen and putting his neck in a brace.
He eventually departed to a standing ovation after lengthly treatment on the pitch. David Meyler replaced him in the 20th minute.
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Chelsea boss Antonio Conte, whose side were 2-0 winners, said: “Everyone at Chelsea wants to wish (Mason) the best. It was a bad accident with Gary.
“After the first half, it wasn’t really good with Gary, but we decided to continue with him.
“It was very bad, this accident. Everyone at Chelsea hopes to see (Mason) recovered and on the pitch very soon.”
The injury led to nine minutes added time at the end of the first half, with Diego Costa giving Chelsea the lead with 90 seconds remaining before Cahill wrapped up victory after the break.
Blues midfielder Cesc Fabregas said: "First, I and all the Chelsea players want to send our best wishes to Ryan Mason."
Tottenham striker Harry Kane, who came through the ranks with Mason, at White Hart Lane, tweeted his support.
Former Spurs striker Darren Bent took to social media to wish Mason well.
He tweeted: "Hope Ryan mason is ok. Looked a bad one."
Mason has played 20 times for the Tigers this season, scoring twice.
Mason's teammate David Meyler was among the well-wishers on Sunday evening.
He wrote on social media: "Hope Ryan Mason is okay. All thinking of you bud."