Jones suffered an ankle injury during Monday's FA Cup win over Reading and is having intense treatment in the hope of being available for the Old Trafford encounter.
"We are working very hard. He has an outside chance for Real Madrid - no more than that," Ferguson said.
Jones will certainly miss Saturday's trip to QPR, and Ferguson knows his absence from the Real Madrid game would cause him a headache given how well the former Blackburn man performed in the first leg last week.
"He is a young man who went into a tackle too brave and was a bit off-balanced," said Ferguson.
"He certainly won't be fit for the weekend."