John Terry regularly offers the impression that he is hard enough and brave enough to attempt to run off a broken leg. That he has been stood down from Chelsea's Premier League showdown at Manchester City with a calf problem has not only cut him to the core but it has offered an indication as to the level of concern about the injury.

Roberto Di Matteo took the decision after consultation with Terry and the club's medical staff. The captain, as ever, wanted to play and he felt he could have done but he agreed that it was probably in everyone's interests if he did not. He feels sure that he will be ready for Saturday's derby against Tottenham Hotspur at Stamford Bridge.

Di Matteo is equally certain, although the interim manager did say last Friday that Terry was fully fit for Sunday's FA Cup quarter-final against Leicester City. Terry did not feature, having not trained with the squad since he hobbled out of the Champions League victory over Napoli last Wednesday.

Indeed, it has emerged that Terry has not trained so far this week, either. He was scheduled to have his first proper session on Wednesday morning, after which he intended to travel to Manchester to support the team.

Terry will not play in what is one of the matches of the season because the risks outweigh the benefits. There is the fear that if he did drive himself through it, perhaps with the aid of a painkilling injection, he would be sidelined for the next few weeks, when the tests continue to come. Chelsea travel to Lisbon next Tuesday to face Benfica in the Champions League quarter-final first leg. The City game is the first of seven in a 20-day period.

There is the suspicion that Terry might need to be handled with care during this period however much Di Matteo denied it at a pre-match press conference marked by caginess. If his team defend like the manager did, they will have no trouble in containing a City attack who could yet feature a cameo from Carlos Tevez.

It took several attempts to extract from Di Matteo the details of Terry's injury. He eventually admitted that the tightness in the defender's calf was "obviously a reaction" to him playing "two intense games" after returning ahead of schedule from a knee operation.

Terry played all 90 minutes of the 1-0 league victory over Stoke City and he lasted 98 of the extra-time epic against Napoli. The club were keen to stress that the problem was unrelated to that affecting Terry's knee, which had flared in the FA Cup tie against Portsmouth on 8 January. Terry played on for three matches before he succumbed and missed the next eight.

Di Matteo wanted to give nothing away and he will demand the same of his players. "It's going to be a game where we have to try to prevent Manchester City from expressing themselves," he said, which did not bode well for the spectacle. There were also sceptical mutterings about Roberto Mancini's injury problems in central defence. The City manager said that Joleon Lescott was out and Vincent Kompany had only a 40% chance of playing. "I'm aware," Di Matteo said, "but I don't trust that information."

Smokescreens are in the news at Chelsea. The club have parted company with the 21-year-old midfielder Jacob Mellis after an investigation into how he set off a smoke grenade at the training ground and caused it to be evacuated. The grenade was left over from a paintballing expedition and it follows the incidents of last year which involved the discovery of a knife in the youth-team dressing room and Ashley Cole accidentally shooting an intern with an air rifle.

Di Matteo faces a dilemma over his heavy artillery. Fernando Torres ended his five-month scoring drought with two in the 5-2 win over Leicester and looked as though his confidence had finally returned. But with Didier Drogba ready to return and Di Matteo set on starting with a lone striker, one of the pair will be disappointed, most likely Torres.

Di Matteo offered nothing in the way of hints, up front or at the back. It was put to him that Gary Cahill might expect to retain his place in central defence. "I have a lot options," Di Matteo said. "We will see."

Chelsea travel to Manchester on the back of four wins from four matches under Di Matteo while City have suffered a blip and it feels a little like a must-win for them. Could Chelsea exploit the pressure that City will be under? "We hope so," Di Matteo said. "But we're all under pressure to achieve our targets."

Di Matteo was inscrutable. Without Terry, his cool will face an exacting test.