Newcastle defender Claudio Cacapa is in danger of missing the rest of the season through injury.
The Brazilian, who has endured a difficult start to his Newcastle career, suffered a groin injury in training and faces a spell on the sidelines.
Newcastle expect the former Lyon man to be out of action for up to five weeks which could rule Cacapa out for the remainder of the campaign.
"We have lost Claudio Cacapa for about five weeks," Keegan told the Newcastle Evening Chronicle.
"He pulled his groin in training on Friday and that's why Lamine Diatta was in the squad against Fulham on Saturday."