CELTIC may be without Vakoun Issouf Bayo for their Champions League qualifier against FK Sarajevo on Tuesday after the striker picked up a hamstring injury.

Bayo, who scored in Saturday’s friendly win over Wiener Club-Sport, felt a strain during training on the club’s pre-season tour through Austria and Switzerland.

The Ivorian will now undergo a scan to determine the extent of the injury, and whether or not he is able to play any part in crucial first-leg tie.

“He felt his hamstring in training the other day, there was a little bit of tightness there, so he will have a scan on Thursday in Glasgow to see if there is any extra damage or not,” said Celtic manager Neil Lennon.

If Bayo does fail to make it, Lennon is encouraged though by the form of Leigh Griffiths, who bagged six goals in the three pre-season friendlies Celtic took part in while on the continent.

The forward is still some way short of full match fitness having sat out the last seven months due to his fight against depression, but his four-goal showing against St Gallen’s under-21 side on Tuesday lunchtime pleased his manager.

“He got four [in the St Gallen game], and it is what he is good at,” Lennon said. “He keeps working away and he scored two brilliant goals today which will give him confidence going forward.

“He scored an amazing goal, and even when he lobbed the goalkeeper, it was just instinctive. So, it is nice to have that sort of player back in and around us again.

“Jack (Hendry) came through, Griff did 80, Sincy (Scott Sinclair) did 80, (Nir) Bitton did 80 and they are all fine.”

Celtic are still waiting to hear the fate of centre-back Jozo Simunovic, who was sent off for serious foul play against St Gallen on Tuesday night after catching opponent Boris Babic with a high boot, but it is unlikely he will face any disciplinary action.

Referee Fedayi San did report the incident to the Swiss FA, who will in turn report it to their Scottish counterparts, but even if Simunovic is to be suspended it would likely be for domestic competition only.

Should the worst-case scenario unfold though, and he is ruled out of the Champions League qualifier in Sarajevo, Lennon is certain that new signing Christopher Jullien will be sufficiently up to speed to step into the breach.

“It’s a good job we’ve got Jullien in the building,” he said. “Obviously, we’ve got Jack Hendry as well who can come into our thinking. So, we’ll cross that bridge if we come to it.

“Certainly, since I’ve come back to the club, Jozo has been very, very good. He’s been great.”

Celtic returned to Glasgow yesterday afternoon after their 10-day pre-season European training stint, and Lennon was delighted with the application shown by his players throughout what was a demanding camp.

“We’ve worked really hard, and you saw a bit of fatigue kicking in towards the end [of the St Gallen game], which was totally understandable at this stage,” he said

“We’ll just get through it and get the benefit from it. Now we’ll have a day or two off, and then come back on Friday ready to go again.

“It has been a really good trip.”