Crystal Palace fear Chelsea will recall on-loan defender Trevoh Chalobah early in January.
Hamstring injuries to Chelsea centre-backs Benoit Badiashile and Wesley Fofana have left the Blues light in defence.
Rather than enter the transfer market this month, Chelsea have been considering bringing Chalobah back as cover.
Chalobah joined Palace on loan on deadline day last summer.
Chelsea have already recalled Argentinean defender Aaron Anselmino from his loan at Boca Juniors, though the 19-year-old is not expected to play an immediate first-team role.
Speaking on Tuesday, Palace boss Oliver Glasner admitted Palace could lose Chalobah for the second half of the season.
“It’s a tricky situation,” he said. “I want to always be honest. Chelsea has the possibility to call him back from loan.
“There’s a little bit of uncertainty at the moment: will they do it, when they’ll do it. We need clarity, he needs clarity.”
Palace play Leicester in the Premier League on Wednesday.
“Let’s see [whether he plays],” Glasner said. “Maybe Trevoh is involved, or not.
“He wants to stay here, but it’s a decision Chelsea can take. We are passengers; we are not the pilot who is flying the plane.”
Glasner added: “My wish and Trevoh Chalobah’s wish is that he stays with us. Chelsea loaned him to us to give him minutes, to improve his game. This is what he did. But I think he’s not finished. It’s a one-year loan deal. But we’ll see.”
