Celtic right-back Alistair Johnston is set to be out of action at least until after the November international break, but manager Martin O'Neill says his latest hamstring injury is "not too bad".

The Canada international missed the bulk of last season with a hamstring problem and suffered a similar injury in August.

However, O'Neill says the issue that forced Johnston off only 21 minutes into his comeback appearance at Hibernian on Sunday is "not the same injury".

"He got a scan and it's not too bad," the Celtic boss said. "I think there are three muscles in the hamstring and it's one of those, but shorter term for him."

The 28-year-old will miss games against Dundee United, Falkirk, Besiktas and Kilmarnock if he is ruled out until next month's international interval.

Prior to Wednesday's visit of United, O'Neill added: "I probably can't see him being involved before the international break, but after that, that's what they're thinking about.

"Even in the spell that he was on [the pitch on Sunday], he looked commanding, he looked a real player.

"But he's very philosophical about it all, he's taking it in his stride and I think he's really happy with what the scan has shown."