A team-bonding meal arranged by Chelsea manager Antonio Conte has been blamed for Victor Moses's illness before the Premier League pacesetters tackled Manchester United last weekend.
The Nigeria international was one of the three players struck down by a virus before the trip to Old Trafford, the others being Diego Costa and Marco Alonso.
Our source said the virus could have spread because of a team-bonding meal on Thursday night.
Moses, 26, missed training the following day and was among the Blues traveling party to Manchester despite being ill.
The right wing-back was far from his best against The Red Devils had to be substituted eight minutes into the second half.