Zak Whitbread's hamstring injury could force Paul Lambert to make a late foray into the transfer market.

Lambert conceded following City's 3-1 defeat against Chelsea he would now have to review the situation ahead of Wednesday's August deadline after losing a third central defensive option barely a fortnight into the new campaign.

Whitbread pulled up sharply following a mid-air challenge with Didier Drogba and was replaced by Anthony Pilkington on the half-hour mark.

Dani Ayala had already been ruled out for 'a few months' with a knee problem suffered in the Carling Cup defeat to MK Dons whilst fellow central defender Elliott Ward has been sidelined for the opening weeks of the season with an ankle injury on the club's German summer camp.

Lambert now has only Ritchie De Laet and Leon Barnett available as his fit senior centre-halves. John Ruddy's red card at Stamford Bridge also leaves Lambert with just young back-up Declan Rudd available for the Carrow Road Premier League visit of West Brom on September 11 following the international break.

England youth international Jed Steer is currently on loan at League One Yeovil – but it's City's central defensive jinx that continues to blight an encouraging start to top-flight life for Lambert's men.

'Zak has pulled his hamstring. Wardy is out, Dani is out and now Zak is out so that might be something we have to look at now,' said Lambert.

'The first three games show me we deserve to be here on merit and we'll do everything we can to survive. If we keep playing like that then we'll be okay. In the first three games we have not been torn apart by anybody. As I've said, we are new to it and we'll keep on learning from every game, but I am delighted with how we are playing.

'We knew they would come out of the blocks because they are the home team and the onus is on them, but we weathered it. Our performance was extremely high, but sometimes you get that – you get beaten by a bit of controversy but, performance-wise, I was as proud as anything.'