Chelsea v NK Maribor Stamford Bridge, 7.45pm, UTV and Setanta Ireland

Eventually José Mourinho could take no more, his patience worn thin by questions about one man's troublesome hamstring. "I don't speak about Diego Costa, " the Chelsea manager said. "I don't want to speak about injured players. If injured, they're injured. If he's not here, he's not here."

Costa is definitely not here, at least for the time being, but he remains impossible to ignore, such is the impact he has made during his short time at Chelsea. Having missed Saturday's victory over Crystal Palace, the striker will be absent for tonight's visit of Maribor in the Champions League, after what Mourinho described as an "almost" hamstring injury progressed into an actual hamstring injury, and Chelsea's primary concern now is ensuring Costa is fit for Sunday's trip to Manchester United.

Not training

“It is the same problem he’s having,” Mourinho said. “But now an injury, not an almost injury. It’s simple. He’s not training because he’s not in condition to do so. I have no idea how long. Tomorrow he cannot play. The weekend is not important but he cannot play tomorrow.”

Although Mourinho would not confirm the extent of the injury – “you want to know too much,” he winked – the fear always exists this is an elaborate double-bluff, that there is no chance of Costa not starting against United. There was similar talk before last month’s game against Manchester City and Costa played.

He will not play tonight and Loïc Rémy will again be given a chance to remind us of his qualities, while Mourinho has Didier Drogba in reserve. "Costa is our best scorer and very important but we have two great strikers available and I'm sure we will not have any problems," the midfielder Nemanja Matic said.

Mourinho shook his head when asked if he would rest players against Maribor with a view to keeping his side fresh for the trip to Old Trafford; not that injuries to Ramires, Mikel John Obi and André Schürrle have left him with much room for manoeuvre. "I don't have Manchester United in mind, I have Maribor in mind," Mourinho said. "I don't rest players."

Unbeaten

Respect was offered to Maribor, who are unbeaten in eight Champions League matches this season. The Slovenian side are second in Group G after their first two matches, having drawn at home to Sporting Lisbon and away to Schalke, and Mourinho will not underestimate them as Chelsea seek to cement their position at the top of the group. He will recall that Chelsea were held by Schalke in their previous European home game. Missing that night? Costa.

Chelsea's desire to wrap Costa in cotton wool is understandable given he has scored nine goals in his first nine matches since his £32m move from Atlético Madrid. Mourinho was frustrated to see him start twice for Spain in their recent European Championship qualifiers, leading him to criticise national associations for not communicating with clubs enough.

“There are no rules, no laws to protect us, just the mentality of the national coaches and teams,” he said. “It’s up to them to take good care of the players or to think in a selfish way. It’s up to them, not to us. I’m not the kind of guy to tell players not to go or to pretend they have problems.”