Andy Carroll suffered whiplash during West Ham's game with Crystal Palace
The striker scored with a spectacular, acrobatic scissor kick during last week's 3-0 win over Crystal Palace.
But at the end of the match he was feeling a problem with his neck and had to sit out training earlier this week.
Manager Slaven Bilic was surprised by the unusual diagnosis, but still expects his big frontman to be fit for the trip to Teesside.
"He's got a whiplash injury, that's what I was told from the physios," said Bilic.
"Then I went to the dictionary basically to find out what that is. It was a sore neck, but hopefully he will be okay.
"It was at the end of the game, I don't know how he got it.
"He then trained Tuesday very hard, he was brilliant in training, but then reported some neck pain. But as I say, hopefully he will be okay.
"We have a few with knocks – Winston Reid has a painful one and Sam Byram has a knock on his knee, it was swollen and he missed training on Wednesday.
"Also Sofiane Feghouli missed training on Wednesday because of a minor problem with his Achilles.
"But I'm very optimistic that all of them are going to be fit for the game on Saturday."