Despite training for only three days this week, Terry returns for Chelsea against Everton, a game Carlo Ancelotti is desperate to win after taking four points out of 15 in November.
Ancelotti criticised his team on Friday, accusing them of lacking desire, personality and organisation without their captain, who is finally able to play again without the pain which forced him to miss five games.
Struggling on: Terry returns to action but his nerve issue persists
Terry, who is 30 on Tuesday, has been advised to adopt a new training regime in order to cope with the problem. He will now focus on strengthening work on the gluteal muscles in his bottom in order to release the pressure on the piriformis muscle near his pelvis, which is interfering with the sciatic nerve and causing the intense pain in his thigh.
'This is the right way,' said Ancelotti.
'For the rest of his career he has to have control of his body. He has to do individual work to protect his back. He has to manage it all the time to maintain good strength in his glutes but the problem has gone.
'The integrity of his body is good. He is playing without pain, without tablets, without injections. He went once to Milan and, after that, he's had treatment with our staff. Maybe he won't be 100 per cent in the next game because he has only trained for three days but that is not important because he brings other things. He can speak across the defensive line, he can instruct and lead the team. He is our captain.
'We need his personality. It is important to win this game. It may be the most important game of the season and I will put pressure on my players. I want to see everything: character, personality, good play.'
Chelsea took only one point from Everton last season and the Merseysiders have drawn on their previous four visits to Stamford Bridge, but of deeper concern for Ancelotti is recent form. His team were beaten 3-0 by Sunderland in their last Barclays Premier League home game, the worst display of a month which also included defeats at Liverpool and Birmingham and a draw at Newcastle.
All or nothing: Ancelotti believes Chelsea must beat Everton in order to challenge for the championship
'Everything was wrong,' said Ancelotti.
'We weren't 100 per cent focused in the games we didn't win. In Birmingham, where we played very well, and at Newcastle, there wasn't a 100 per cent desire to win. You can have desire at 99 per cent but that is not enough.
'Sometimes to move on from a bad moment, you have to do more than expected. We didn't do enough. We know this is a bad moment and it is not finished. We hope to finish it against Everton but it will be difficult against a very strong team.
'A victory would resolve everything. Then we play three teams who think they can win the title - Tottenham, Arsenal and Manchester United. If we have December as we had November, it is obvious we will struggle to win the title.'
He's back: Michael Essien returns from suspension
Michael Essien returns from a three-match ban. The midfielder was shown a red card for a reckless challenge in the final seconds of Chelsea's last Premier League win against Fulham.
'He knows he made a mistake and I'm sure he won't repeat it,' said Ancelotti.
'We have spoken about this, about more control, especially in the last minute of a game.
'We haven't just missed his muscle, we have missed his character and personality. He brings that, like Terry. We've had problems scoring from midfield and he can solve that.'
Without Terry, Essien and Frank Lampard and with results failing, Ancelotti felt the pressure to pick Didier Drogba despite the striker's battle to recover from malaria.
'Normally with malaria you are out for two months,' said Drogba.
'I have lost weight. My body has not recovered fully yet but I am much better. I am improving.
'A few weeks ago I was in poor condition. I was sick and now I can make runs and create space and some good opportunities. It's just the goals that are missing and they will come.'
It is symptomatic of Chelsea's patch-up campaign that Drogba has been forced to soldier on at a time when Alex played two games in defence with an injured knee.
Alex flew to Brazil this week to have an operation which will rule him out for up to eight weeks.
Ancelotti confirmed that defensive injuries may force him to dive into the transfer market next month, with David Luiz a long-standing target.
Benfica were asking for £50million for the centre half last summer but have slipped eight points behind Porto at the top of the Portuguese league and there are suggestions they may be ready to accept much less.
Chelsea might be willing to do business at £30m.
Centre of attention: Chelsea are considering a big-money move for Benfica defender David Luiz
'We have to look at injuries,' said Ancelotti.
'It is important to look at John Terry and Alex and maybe in January we can move.'
As further proof that he does not think teenager Jeffrey Bruma is ready to step up, the Chelsea boss also confirmed he could be allowed to move on loan to PSV next month.
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