Jose Mourinho admitted Chelsea are struggling without John Terry after watching the Blues drop two points in the Premiership title race.
And he is braced for the possibility of continuing without Terry for the foreseeable future after revealing the England skipper may require surgery on his recurring back problem.
Terry watched from the stands as Chelsea's Premiership title defence suffered a setback when a bizarre Michael Essien own-goal handed Reading a point at Stamford Bridge.
He has now missed the last four matches and Mourinho is waiting on a decision from his medical team to see whether the 26-year-old needs an operation.
'I've no idea when John will be back,' he said.
'I read something in the press a few days ago saying he'd be back soon but they obviously know more than me, because I have no idea.
'Up until now no-one has told whether he will go for surgery or need some other type of treatment.
'I don't know how long he will be out for - three days, three weeks or three months, I don't know.
'I want John to be back at soon as possible. The medical department will have to make a decision soon.
'The medical department have said surgery might be a possibility. I want them to make a quick decision.'
Mourinho is also waiting for an update on Joe Cole's fractured foot with the England midfielder possibly also facing an operation.
'It's the same with Joe Cole. I don't know if he will need surgery or not,' said Mourinho.
'One medical philosophy is that surgery is best, another says he should wait for the bone to heal.'
Chelsea looked set to replace Manchester United at the top of the Premiership, if only temporarily, when Didier Drogba nodded home a precision Shaun Wright-Phillips cross to restore their lead.
Drogba had started the scoring in the first half when he rose high to meet Frank Lampard's corner only for Leroy Lita to snatch an equaliser following excellent work from Glen Little.
But an 85th-minute blunder from substitute Ashley Cole allowed Reading to steal a share of the spoils.
Kevin Doyle crossed but Cole, who was under no pressure, rushed his clearance, hitting it straight at Essien who unwittingly deflected the ball into the net.
Essien finished the match in central defence and Mourinho admitted the absence of Terry and goalkeeper Petr Cech is putting pressure on the strikers.
'To lose Petr and John at the same time is a very difficult problem to solve, especially in a squad without more central defenders,' he said.
'We lost Gallas and Robert Huth in the summer. We don't have enough cover so at this moment we are having problems.
'Normally for Chelsea three consecutive matches would mean three clean sheets but at this moment in three consecutive matches we have conceded six goals.
'So for us to win matches right now we need to score three times. Sometimes we'll do it, sometimes we won't.'
Mourinho had no complaints with today's outcome and admitted Reading, who were tenacious throughout, deserved their point.
'That was a fair result. We did enough to win because we scored two goals and could have scored more,' he said.
'I don't think I can complain about the players. For example the game at Wigan was easy but we made it hard for ourselves. Yes, I had reason to be unhappy with them then.
'But today no because Reading made it difficult for us. When the opponents do well and create problems, you can't complain, only praise the opposition.
'They got a point at Stamford Bridge. Of course we want to win every game and we are never happy to draw, but there is no criticism aimed at my players because they did the best they possibly could.'
Reading controlled spells of the second half with Kevin Doyle and Brynjar Gunnarsson missing chances to equalise before Essien did the job for them.
Royals boss Steve Coppell said: 'It was interesting the way the game developed. I thought it was stagnant for long periods of the first half.
'We had a defined gameplan and the players stuck resolutely to that. I think 1-0 down is a precarious position to be in put we really pushed on.
'There was a real determination in the dressing room. The players were very positive and the momentum was with us for the second half.
'Once we got back in I thought we might have gone on to win the game. We had a bit of fortune for the second goal. We are pleased with the point. We haven't played well recently.'
The build up to the match had centred what treatment Stephen Hunt and Ibrahima Sonko could expect following last October's controversial encounter at the Madejski Stadium.
Petr Cech sustained a depressed fracture of the skull following a challenge from Hunt and Carlo Cudicini was left with concussion from a similar incident involving Sonko in the same match.
The Reading duo revealed they had received hate mail and death threats from Chelsea fans as a result of the injuries, cranking up the tension ahead of today's return at Stamford Bridge But Hunt was named on the bench, taking some of the sting out of the home crowd's hostility, while Sonko approached his task of keeping the Chelsea quiet with impressive calm.
Coppell said: 'This game had been hanging over Hunty in recent weeks and he hadn't been playing well. I wanted to tinker with the way we were doing things.'