Southampton are confident Fraser Forster’s value will rocket to more than £20million by the end of his season at Celtic, Football Insider understands.

The goalkeeper, 31, has reignited his career during his Parkhead load after slipping to third-choice shot-stopper at the Premier League club.

A Southampton source has told Football Insider the club are closely monitoring Forster and his performances, and believe he is once again developing into a major asset.

The 6ft 7in giant was given the green light to go to Celtic back in August after finding himself behind Angus Gunn and Alex McCarthy in the Saints pecking order.

He has made an instant impact during his second spell for the Hoops, immediately claiming the number one shirt ahead of Craig Gordon following an injury to the first choice Scott Bain.

Forster’s form is such that he is being touted for an England recall and he is set to have plenty of options opening up to him next summer.

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He is unlikely to want to stay at Southampton unless he is the number one – the club have high hopes for Angus Gunn – but his £70,000-a-week wages almost certainly puts him out of Celtic’s reach.

A more likely scenario is a move to another Premier League club in next summer’s window.

Forster has made 15 appearances for the Hoops since his return, keeping seven clean sheets and conceding just 10 goals.

His grip on the number one jersey is set to face strong competition from Bain, who is close to recovering from a dislocated figure sustained in August.

In other Celtic news, it can be REVEALED that the club have set their sights on blowing Rangers away in race to sign red-hot striker.