The playmaker limped off late on in Monday's 2-0 victory over Stoke after a tackle from Jonathan Walters.
Oscar will hope for a recall after being left on the bench at the Britannia Stadium.
Boss Jose Mourinho believes footballers playing in Britain deserve respect because of the hectic festive fixture programme.
Beginning with Monday's win, the Blues will play five matches in less than two weeks.
Boxing Day sees the visit of the Hammers while further Premier League matches against Southampton and Tottenham follow before an FA Cup third-round clash against Watford.
"It's very difficult," said Mourinho.
"I have lots of respect for the players in this country
It doesn't matter - English or not English
The moment you are a football player in this country, I respect you a lot.
"At this moment the German guys are on the beach, the Spanish guys are in the Maldives getting sun - everybody else is doing that.
"But in this country you play on the 22nd, you play on Boxing Day, you play on the 28th, you play on New Year's Day
There is no Christmas - just football, and I think (the players) deserve respect.
"The supporters all around the country give them that respect because every stadium is sold-out
And I think the way to do it is with the kind of professionalism my players have shown."
West Ham manager Sam Allardyce will welcome midfielder Mark Noble back into his squad.
Noble has missed the last four games with an Achilles problem but has handed Allardyce a boost by returning to training in advance of the festive fixtures.
James Tomkins (hamstring) is the only absentee for the Hammers - with James Collins ready to step in alongside Winston Reid in the heart of their defence.
Allardyce said: "We've got the two hardest games over 48 hours over Christmas - Chelsea away and Arsenal at home in the space of 48 hours is a big demand for us, even though we're on top of our game at the moment.
"Getting through these two games is going to be a tremendous effort for all the players selected, and hopefully they'll come through for us as they have done for most of this season."
Source : PA
Source: PA