John Terry will see a specialist in France to ascertain the seriousness of his back injury.
The England captain has missed Chelsea's last four games with the problem - four games in which the champions have conceded six goals.
Initially Chelsea believed the problem was not serious, but the Mirrorreported today that Terry will fly to Bordeaux to have exploratory surgery on the disc problem in his lower back.
This procedure will decide whether a further operation is needed.
If not then Terry could return within a couple of weeks, but if further surgery is required then he could be on the sidelines for six weeks or more.
This would mean Terry would not only miss a vital Premiership games (including a trip to Anfield to face Liverpool) but he could also be out for Chelsea's Champions League second round clash against FC Porto.
Jose Mourinho's side have missed their captain in a big way over the last few games, culminating in Michael Essien's comical own goal that handed Reading a share of the points on St Stephen's Day.
If Terry is out for a long period then Mourinho may adjust his transfer plans and buy another centre back in the transfer window, with Khalid Boularouz and Ricardo Carvalho their only other central defenders.
