Manchester City boss Mark Hughes is sweating over Jo, Richard Dunne and Ched Evans ahead of Wednesday's clash with Middlesbrough.
Jo missed Sunday's win over Stoke with tonsillitis and appears unlikely to make the trip to the Riverside.
Captain Dunne has respiratory issues after hurting his chest earlier this month, whilst Evans is struggling with a knee problem.
Both players were forced off in the win over Stoke after starting the match,
"Jo was not in any fit state to participate, even as an option on the bench," City boss Hughes told the club's official website.
"He may be better in a couple of days but we will have to wait and see.
"Richard had to come off because he was struggling with his breathing. He got a bang on his chest a few weeks ago that is still hindering him.
"Ched got a bang just above the knee and will be very sore. He is a doubt for Wednesday."
Fit-again Nedum Onuoha and Daniel Sturridge are both on stand-by for recalls after coming on for Dunne and Evans, respectively, at Eastlands.