With Robin van Persie already ruled out for four weeks with a thigh problem, the last thing Moyes needs is to be without the man who has carried United through much of a troubled campaign.
However, when Rooney's name was missing from the squad that booked a Capital One Cup semi-final encounter with Sunderland next month thanks to a 2-0 win at Stoke, there were obvious concerns among the United support.
But Moyes insists it is nothing serious and the 28-year-old may yet play a full part in the festive programme as United look to get their Premier League campaign back on track.
"It's a groin strain," said the United boss.
Then, when asked whether Rooney could face West Ham, Moyes replied: "He has got a chance, yes."