The News of the World says the United defender has been carrying the injury for months.
United physios are now demanding the England ace gets the rest and treatment he needs to cure the problem.
Ferdinand was left out of United’s 2-0 win over Blackburn on Sunday.
The expierienced defender has kept on helping the club despite being less than 75 per cent fit in recent weeks.
An Old Trafford insider told News of the World: “All Rio wants to do is play pain free.
“This injury first flared up before United’s Champions League quarter-final against Porto last season and it has gradually got worse.
“Now the problem has been identified and needs to be cured, whether it takes two, four, six or eight weeks.”
