Chelsea and England captain John Terry is back in training less than 24 hours after undergoing successful surgery to cure his troublesome back injury.
Terry injured his back in training earlier this month
The 26-year-old defender was pictured on the club's website jogging at Chelsea's Cobham training ground.
But Chelsea club doctor Bryan English has refused to reveal how long the centre-half will be out of action.
"I won't say exactly how long he is going to take to recover," English told the club's website.
English added: "When I hear so-called experts say that he's going to have
a six-week recovery, when people comment when they don't know his
pathology - I have a bit of a problem with that."
Chelsea have conceded six goals in three league matches without Terry and have fallen four points behind Premiership leaders Manchester United.
But having sold both William Gallas and Robert Huth, manager Jose Mourinho has admitted the continued absence of Terry has left him short of defensive options.
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The Blues have already conceded 15 league goals so far this season - only seven fewer than they did over the whole of the last Premiership campaign.
Terry's injury could also hit England, who are due to play Spain at Old Trafford on 7 February.