Manchester City manager Manuel Pellegrini has claimed that captain Vincent Kompany may not return to action until the "last part" of the season.
The Belgium international has not featured since City's 4-1 win over Sunderland on Boxing Day, when he suffered a fresh calf injury after coming on as a second-half substitute.
In Tuesday's press conference, Pellegrini revealed that Kompany is working with the medical team in a bid to discover the root cause of the problem.
When asked when the defender is likely to return, Pellegrini told reporters: "Its difficult to know. We are still trying to find out the reasons for so many injuries. Myself I'm not so sure, maybe the last part of the season."
Kompany has had 13 calf injuries since he joined City from Hamburg in August 2008.