Celtic coach John Kennedy believes Efe Ambrose has begun to prove his worth to manager Ronny Deila.

Ambrose has recently returned to his favoured centre-back role following the departure of Virgil van Dijk and an injury to recent signing Jozo Simunovic.

Celtic have kept three consecutive clean sheets in the process and, although Ambrose was sent off for a last-man foul against Hearts on Saturday, it was in injury-time and he was clearing up after Dedryck Boyata allowed Sam Nicholson to run through on goal.

Simunovic should recover from an ankle injury in time for the Europa League clash with Fenerbahce at Parkhead on Thursday but Ambrose is ready to continue if needed.

Speaking about the Croatian defender, Kennedy said: "We hope he's okay. He has started light training again so hopefully on Tuesday he will pretty much join in the full session and come back into it. But the big positive is Efe has come in and done really well for us.

"He's been patient. He has found himself out of the team when maybe he thought he might have had a chance, but he has trained well and he has certainly come in and done a great job for us in recent weeks. So there is competition there as well."

Ambrose played right-back for Nigeria in the 2014 World Cup but his standing in Deila's plans was evident when the inexperienced Saidy Janko was preferred for the Champions League qualifier at Malmo after Mikael Lustig got injured.

But Ambrose has been given a chance, albeit through necessity, to show Deila he can perform in the centre.

"He has done it under Neil Lennon for a long time," Kennedy said. "He has made some errors in the past, as all players do. He has probably been unfortunate at times to find himself out the team.

"But he is a great professional, a terrific player to work with, and when he is concentrated he can put in good performances like he has shown in recent weeks."

Kennedy admits the visit of Robin van Persie and his Fenerbahce team-mates will be a significant examination.

"Ajax were a big test but this is another top side," the former Celtic defender said. "It's going to be a tough one. Van Persie has been out the team in the past two weeks but judging by the way he has come on and impacted the game, I'd be surprised if he doesn't play on Thursday.

"They have great individual players, they are also a team that's in transition with a new coach and a lot of new players. But they are still a top side. One or two results haven't gone their way but they are still a very, very good side.

"It's going to be a tough section to qualify from, but this is what it's all about, Celtic playing in big games and Thursday is a very big one."

Meanwhile, Kennedy revealed talks were ongoing with Carlton Cole following the former West Ham and Chelsea striker's trial at Lennoxtown.

"The last I heard the manager and Peter (Lawwell, chief executive) were speaking to his representatives," he said. "There was no decision made so we will see how things pan out this week.

"He did well last week but he is short on football fitness and he has not done enough football training to get a proper judgement, but we know what he is all about and I think when the club and his representatives speak together, then the deal has to be right if there is one to be done."