Chelsea boss Frank Lampard is confident Tammy Abraham hasn't suffered any long-term injury.
Abraham suffered a hip injury during the Blues' Champions League draw with Valencia - and was forced off at half time as he struggled in pain.
"We'll know by the end of the weekend, he's got some pain and won't be involved tomorrow," said Lampard. "But then we'll know by Monday."
Abraham landed awkwardly on his hip in Chelsea's Champions League clash at the Mestalla and was carried off on a stretcher at half-time.
Michy Batshuayi replaced Abraham off the bench in Valencia and will battle it out with Olivier Giroud to lead Chelsea's line against West Ham this weekend.
Lampard added: "Michy has shown work ethic and quality, which I knew anyway. It's not easy when you're not playing as many minutes as you'd want."