Alistair Johnston is set to be sidelined for six to eight weeks after undergoing an ankle operation.

The Celtic full-back went under the knife to correct a slight ankle knock and will now begin rehab ahead of the new season.

It means Johnston will miss the start of the league season next month and is an early doubt for the first derby against Rangers on September 3.

However, boss Brendan Rodgers is hopeful Johnston can return sooner having "progressed really well" in his early rehab work.

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The Celtic manager said: “Alistair had an issue when he came back from international duty- he has a slight problem with his ankle but he’s had that operation on his ankle, it’s been successful and he’s out here with us.

“It's probably a six to eight-week injury but hopefully he’ll be back sooner than that.

"He’s progressed really well and it’s better to have it done at this stage of the season than some time into the season."

Meanwhile, Cameron Carter-Vickers travelled with the Hoops to their training base in Portugal.

And Rodgers admitted the American is progressing well and should be back involved in first team action sooner rather than later

He said: "Cameron is doing very, very well. He's out on the pitch. He look strong, so he is progressing and is well on schedule to be back. That is good news".

It comes as Mikey Johnston has been ruled out for three months with a back injury.

Rodgers confirmed: “His job is to convince myself and the coaches that he is ready for a place. Sadly for Mikey, he is going to be out for a few more months.

"He had an issue with his back, sadly, so he’ll probably be out for near on three months. 

“But it’s the players’ responsibility and they have to show the quality and consistency and robustness in order to play and that is the job of every player.”