Fraser Forster has been a revelation since re-signing for Celtic.

Frank McAvennie is shocked that Southampton let Fraser Forster re-sign for Celtic on loan this past summer.

Forster joined the Saints in a £10 million deal from Celtic in 2014 [The Scottish Sun] and returned to Parkhead on a season-long loan this year after falling out of favour with the Premier League side.

And it’s fair to say that the big English goalkeeper has been a revelation since coming back to Glasgow.

Earlier this month, Forster posted a Man of the Match performance as the Hoops edged out Rangers 1-0 in a League Cup final, in a game where he saved a penalty from Alfredo Morelos.

And Celtic boss Neil Lennon will be looking for similar heroics tomorrow as Parkhead plays host to a huge Premiership clash between the Old Firm duo.

But club legend McAvennie admits that he’s stunned that Southampton didn’t feel as if they needed a goalkeeper of his class.

He told Open Goal: “How did they let him go? How did Southampton let him go? I just can’t understand it. Can’t understand it.”

Lennon has previously said this month that he would ‘love’ to re-sign Forster on a permanent basis but he won’t be cheap.

His fine form up North means that Southampton can raise the price for Celtic and with his contract not expiring for two-and-a-half years, the Saints do have the upper hand here.

In other news, Report: Tottenham have now made first bid to sign star who thinks Mourinho is brilliant