Derek McInnes is hopeful Aberdeen can secure Europa League progression so he can splash out on another defender.

The Dons boss is facing a defensive crisis ahead of Thursday's second-leg clash against Georgian outfit Chikhura at Pittodrie.

Centre-back Ash Taylor became the latest addition to the Reds' casualty list when he limped off early during the 1-1 draw in Tblisi with a hamstring injury.

The former Tranmere and Northampton stopper requires a scan to determine the extent of the damage but McInnes is concerned.

He hopes to have Greg Leigh back from an ankle knock in time for the return showdown but admits with the NAC Breda loanee still short on fitness, he may have to limit the left-back's involvement when his side kick-off their Ladbrokes Premiership campaign against Hearts on Sunday.

Michael Devlin is also still confined to the treatment room with hamstring trouble, leaving McInnes to admit he needs reinforcements.

Now he is praying his side can free up the money he needs to invest in his squad by seeing off Chikhura and securing a clash with old foes Rijeka of Croatia.

McInnes – who also admits he is braced for late interest in centre-back Scott McKenna ahead of next week's English transfer window – said: "It's not ideal. We had a lot of injuries last season, particularly to our back line.

"We know how important it is to get a steady back four but I've not been able to do that even through pre-season.

"With the budget I've got, you look at maybe ideally having seven defenders but I'm only working with six.

"We're put under a bit of strain as soon as you get two or three injuries in that area of the pitch.

"It's the same in central midfield, where we maybe have four guys who can play in there. We've got a bit more option with wider players and at centre forward but certainly defensively we could do with bringing one more in if we can get through this tie."

Aberdeen raised eyebrows when they dumped Rijeka out of the competition four years ago but McInnes is wary of looking ahead to the potential rematch while Chikhura remain a threat.

The Dons boss – whose side claimed a valuable away goal last week thanks to Sam Cosgrove's second-half penalty – said: "Rijeka is a game we want to be part of and to take them on but we have work to do first.

"Like any cup competition you can't look to far ahead of yourself but just like domestically in the cups here, our intention is to go all the way.

"In this instance in the Europa League, the group stages is where we want to be. That would be tangible success.

"But for me it's one step at a time. If you look to far ahead you can get a belt in the mouth and we can't afford to do that.

"We just have to concentrate on this game because our opponents are good enough to give us problems. Against teams with a technical ability it only takes one moment and you can be out."