This was an accursed result for Roger Johnson, the Wolverhampton Wanderers captain. A replay in eight days' time is, he admitted, the last thing he would have wished for.

From the moment his name was announced with a gratuitous flourish over the PA system before the match to the moment he twisted his ankle and was substituted, the booing around St Andrew's, though by no means universal, was painfully audible.

"I'm disappointed with the fans. I've no beef with them but obviously they do with me now," he said. "The guy announcing my name was probably expecting the fans to clap, but they weren't happy. No one knows the real story behind why I left here, certainly not the fans. They [the club] asked me to do what I did – that's basically it."

Johnson can blame the Birmingham City goalkeeper, Colin Doyle, for ensuring the replay. It was Doyle's wonderful double-save in injury time from Matt Jarvis, then Stephen Fletcher, that denied Wolves victory. Such quality belied all that had preceded it.

"Doyley did well with a couple of great saves at the end. I could have done without that. But I know better than anyone what he's capable of," said Johnson.

It was a poor Cup contest. Hideous, in fact. Barring Doyle's late saves, the only memorable goalmouth activity was when Sylvan Ebanks-Blake skied a shot over from 12 yards when totally unmarked.

For Johnson, injury at least provided escape from the cocktail of tedium and vitriol. "Injuring my ankles is something I used to do a lot as a kid. But over the last six to seven years I've not done it at all," he said. "Unfortunately I rolled it in training on Friday and the physio says that's made it weaker and it went again during the match. It was just the way I landed.

"I had weak ankles as a kid. I used to injure them coming down the stairs, anything stupid. I'd wear strappings and stuff as a kid and I worked hard to strengthen them over the years. I don't know whether it was to do with growing pains – even when I played Sunday football it was prone to rolling."

Johnson has endured a difficult start to his Wolves career and has little currency with the Molineux faithful to compensate for his perceived lack of form. His manager, Mick McCarthy, expects him to return to action within a week. When he does so, more clean sheets will be demanded.

"We should be five games unbeaten now," said Johnson. "The Chelsea game was disappointing. But we got a clean sheet against Birmingham and it's another game we haven't lost."