CELTIC manager Brendan Rodgers isn't overly concerned by a defensive crisis that has ruled out five central defenders for Wednesday's Champions League qualifier against Astana.

Denmark international Erik Sviatchenko was ruled out with a groin problem today after not making the trip to Kazakhstan. 

His absence came after a hand injury to youngster Kristoffer Ajer, long-tern setbacks to Dedryck Boyata and Jozo Simunovic and a lack of match fitness for new arrival Kolo Toure.

Read more: Astana coach Stoilov insists Celtic are favourites for Champions League qualifier in Kazakhstan

The much-criticised Nigerian Efe Ambrose is now poised to start and is one of only two natural centre-backs available along with youngster Eoghan O'Connell.The Herald: Davie Hay believes that Efe Ambrose has had enough chances for Celtic and he shouldn't play again for the Hoops

However, Sweden international Mikael Lustig is also capable of moving into a central role and could be deployed there tomorrow. 

"He's (Sviatchenko) been working well but unfortunately before the game at the weekend he picked up a groin strain which makes him unavailable," said Rodgers.

"We will assess that over the course of the next week and see if he can be available for the second leg.

Read more: Celtic facing defensive crisis as Erik Sviatchenko misses out on Astana clash

"In these games it is always going to be the case of doing the very best that we could with the limited time and numbers that we have.

"But I am confident that whatever team we put out will do their very best, like we did in Saturday's game against Leicester."The Herald: Erik Sviatchenko was not badly injured against Wolfsburg which came as a huge relief to Brendan Rodgers

During that pre-season friendly against the Premier League champions, which Celtic lost on penalties following a 1-1 draw, O'Connell struck the Hoops' solitary goal.

The 20-year-old has been impressing his new boss with his attitude during the close season, Rodgers revealead.

He said: "Both players (Ambrose and O'Connell) have worked very well, In particular, young Eoghan, I have been really impressed with him over the course of the pre-season.

"He is a good size, first and foremost he wants to defend and in the short period I have worked with him, he is good in the air.

"He has been in and around the first team for a few years now.

"He was up against tough opponents at the weekend, even though Leicester have only been back a few weeks, they come back already fit and I thought Eoghan coped with that very well, the speed of their team.

"He has a brain for football, he understands the game very well for a young player and importantly he plays the game well.

"For a young player, if they show those qualities and professionalism I never have any fears of putting him in.

"In terms of Efe, everyone has seen, and people have seen a lot more than I have of him, he knows that if he can cut out mistakes or errors that he makes in games, then you have a very good player because physically he is very strong, very fast, good in the air.

"It's about decision-making and simplifying the game, if he can do that he can be an asset.

"I have no qualms about who I put into the game. The strength of us will always be the team rather than the individual and the team that we put out will hopefully get the result."