The United striker picked-up a knee injury during his debut game against Liverpool at the weekend and manager Alex Ferguson is unsure as to whether the Bulgarian international will have recovered in time for the visit of the Spanish side to Old Trafford on Wednesday evening.
"Berbatov is very doubtful," Fergie has said.
"He got a knee injury on Saturday. He came off for treatment and then played on, but there has been some swelling.
"We'll work hard on that, but we may not have enough time."