Injury problems have been a thorn in Celtic's path throughout the course of the season. They have had key players missing, which has clearly had an impact on what has been a poor campaign by the Hoops' standards. Unfortunately, things do not seem to be getting any better for Martin O'Neill's team.

During the international break, fans are always worried about players picking up issues and making things difficult for the club, especially on the business end of the season.

Most of the time, you are worried about those who are featuring for their national teams. But unfortunately, this time around, it is someone who did not during the recent international break who has returned to Glasgow with an injury.

Alistair Johnston had returned to training leading up to the international break. And he was allowed to join his Canadian teammates in training, even though he was never going to feature.

Unfortunately, it looks like Johnston has now suffered a setback while away with his national team.

According to The Celtic Way, O'Neill said regarding the Canadian international right-back: "He went away with the Canadian national side, was doing some running and had a bit of a setback on his final day of training, which was really disconcerting for us.

"In the wider scheme of things, for the length of time he’s been out, hopefully it’s not too bad.

"But it has delayed things a little bit here. We were hoping to have him, I’m not saying for this weekend, but we were hoping to have him in a couple of weeks, maybe having played some bounce games.

"That will just have to be parked and put to the side for the moment. It’s a shame.

"He went with the national side and was only ever going to do little bits of training, which is all he did. If we’d had a full quota of payers here, then he’d have stayed with us.

"We felt there might be a benefit of being away with the national side, just in a different environment, as he hadn’t met up with them for some time.

"Obviously, they’ve got the World Cup, and he’s a big player for them. So, we all felt it was the best idea. It was only on the final day that he felt a bit of a niggle."

Johnston initially suffered a hamstring injury back in August. He would return to fitness a couple of months and Brendan Rodgers put him straight into the starting XI, which was a mistake. He reinjured himself in that same game and had to undergo surgery.

Now, several months later, Johnston was closing in on a return but has suffered another setback. In the grand scheme of things, many will start worrying whether he is even capable of remaining fit for any consistent length of time moving forward, considering the number of issues he has had to deal with lately.

The only positive is that this setback does not look to be a major one and Johnston is expected to be back in action before the end of the season. As O'Neill said: "Don't hold me to this.

"But there must be a fairly good chance that he [Johnston] will play here [Celtic] before the end [of the season].

"He was on course, hoping that having come back from Canada, that we would have been able to have done something with him this week in terms of a bounce game.

"That’s been put on hold so I couldn’t tell you but again I don’t think he’s far away."

The timing of the setback is a horrible one for Celtic. Julian Araujo is currently out injured as well and has returned to Bournemouth to undergo treatment. He might not even play again this season. And considering he is only on loan, we might very well have seen the last of him in the green-and-white jersey.

Colby Donovan has also been dealing with some fitness issues lately but the positive is that he was pictured in training recently. Do not be surprised if you see him in the starting XI at the weekend.

O'Neill has been left with very little in the name of options though. And in a period of time when Celtic need to be close to perfect in terms of results, that is far from ideal.

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