Assistant boss Neil McDonald could not confirm reports Nolan has been ruled out for eight weeks, as the Hammers await medical reports after a foot injury was exacerbated in Monday's 3-2 Barclays Premier League loss to Tottenham.
"We're still waiting for the results to come back," McDonald said. "His toe's very, very sore. He's had problems in the past with it, all season really. And he got a really good kick on it."
He continued: "I'd imagine he'll not be available for Saturday (at Stoke) and we'll see how the results come back and we'll see where he's at. He has been playing through the pain barrier. We'll assess it in the next couple of days."
The challenge by Moussa Dembele on Nolan angered West Ham boss Sam Allardyce, who deferred his pre-match press conference duties to McDonald, and the possibility remains that the 30-year-old will miss a significant portion of the final 11 matches, with the Hammers' top-flight safety still to be assured.
United sit 14th on 30 points ahead of the trip to the Britannia Stadium but have just three wins in 18 games in all competitions, including the 1-1 draw with Stoke which marked the start of that poor run.
McDonald admits he is anxious but he is trying to encourage the squad to look upwards, rather than worry about their six-point cushion to the relegation zone.
"We've always looked up the table this season," McDonald said. "We've always tried to get into the top 10 and with a good result on Saturday we can push ourselves a little bit closer to that.
"The away form hasn't been as good as what we would've liked. I think our home form's been really, really good, even though we've lost a couple.
"We have to address that. We have to be a little bit more physical away from home and make sure we keep things tight, try to keep a clean sheet. If we can do that, that gives us a good chance to get back to winning ways on our away form."