Deontay Wilder was rushed to hospital following his TKO defeat to Tyson Fury.
Wilder skipped the post-fight press conference which comes after the in-ring interview to head to hospital.
It is believed he was taken as a precautionary measure following his seventh-round defeat.
Fury had Wilder on the ropes throughout and controlled the contest from start to finish.
The Gypsy King won the WBC heavyweight world championship and Eddie Hearn hinted a fight with Anthony Joshua could be on the cards.
He said: “No need for a third let’s go straight to it in the summer! #undisputed.”
Afterwards Fury said: “A big shout out to Deontay Wilder.
“He came here tonight and he manned up and he really did show the heart of a champion.
“I hit him with a clean right that dropped him and he got back up.
“He is a warrior.
“He will be back.
“He will be champion again.
“But I will say, the king has returned to the top of the throne!”
Wilder admitted he was beaten by a better man after struggling to deal with Fury’s tempo and front-foot strategy.
He said: “The best man won on the night.
“My coach threw in the towel but I’m ready to go out on my shield.
“I had a lot of things go on coming into this fight but it is what it is.
“I just wish my corner would have let me go out on my shield, I’m a warrior.
“But he (Fury) did what he did and there are no excuses.”