The striker, who only returned from five months out with a broken leg in Sunday's FA Cup defeat to Bolton, went over on his ankle in morning training and faces a fitness test.
Down and out: Zamora (left) has only just returned from a lengthy spell out
Midfielder Steve Sidwell has been ruled out for four weeks after damaging knee ligaments, while Philippe Senderos and Diomansy Kamara will also miss Sunday's match with back problems.
Provisional squad: Schwarzer, Stockdale, Pantsil, Hangeland, Hughes, Baird, Briggs, Etuhu, Davies, Murphy, Duff, Dempsey, Gudjohnsen, Kakuta, Gera, Dembele, Salcido, Greening, Johnson, Zamora, Halliche.
CLICK HERE FOR THE WEEKEND TEAM NEWS IN THE BARCLAYS PREMIER LEAGUE Explore more:People: Philippe Senderos, Bobby Zamora