Slaven Bilic does not think an injury to Winston Reid picked up in the home defeat by Chelsea is serious.
The West Ham centre-back was taken off after 64 minutes at the London Stadium, where Chelsea won 2-1.
But Hammers boss Bilic is optimistic that Reid will be okay.
He said: “Hopefully it’s only a cramp. I spoke to the medical staff, but you never know.”
Speaking to reporters following his team’s loss, Bilic said he doubted Chelsea will slip up during the title run-in.
Goals from Eden Hazard and Diego Costa clinched a victory that moved the Blues 10 points clear at the top of the Premier League with 11 matches left to play.
Bilic said: “They’re not going to become casual. They looked very serious.
“I can see them staying top with the quality they have and how solid and concentrated they are, and most of all how physical they are.”
But Chelsea boss Antonio Conte says he is taking nothing for granted.
Conte said: “Now in this period it’s very important to live with the pressure in the right way, especially after you know your opponents won their game the day before.
“For sure I trust my players. I must have confidence in them. I think that, until now, we are deserving of staying on the top of the table.
“It’s important to keep this position but it won’t be easy because Tottenham and Manchester City chase us.