Martin O’Neill has been forced to make changes to his Celtic defence in recent weeks, with injuries leaving him short of experienced options.

But there was an interesting sight at Lennoxtown on Wednesday as the Hoops prepared for Thursday night’s Europa League clash with Celta Vigo.

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Cameron Carter-Vickers and Alistair Johnston spotted in Celtic training

Sky Sports Scotland shared footage of Cameron Carter-Vickers and Alistair Johnston taking part in Celtic’s training session ahead of the visit of the Spanish side.

Johnston has been missing since August, while Carter-Vickers hasn’t featured since the defeat to Rangers on September 20.

Both players were involved on Wednesday morning, although it remains to be seen whether either will be considered for Thursday’s game.

O’Neill had already indicated that Carter-Vickers was unlikely to feature against Celta Vigo.

In O’Neill’s recent injury update, the Celtic manager said: “Cameron will, I think the earliest we would probably be seeing him is the Hibs game (on Sunday).”

Seeing Carter-Vickers back on the training pitch is a welcome development, even if Thursday’s European fixture comes too soon for him.

There has been no confirmation yet on whether Johnston is ready to return to the matchday squad.

Dane Murray has been filling in for Celtic

Dane Murray has started Celtic’s recent matches against Benfica and Hearts in Carter-Vickers’ absence.

The young defender had a difficult night in Lisbon but kept his place for Sunday’s 7-1 demolition of Hearts at Parkhead.

Former Celtic defender Jim Duffy has already identified two areas Murray needs to improve, although O’Neill has continued to put his faith in the youngster.

Carter-Vickers’ return to training gives O’Neill something else to consider ahead of Sunday’s trip to Hibernian, which was the manager’s original target for the American’s comeback.