The 22-year old Dutch defender has produced a stellar debut campaign for the Bhoys after joining from FC Groningen in the summer and is being tipped to move to a top club for a massive fee in the near future.
"I definitely think Virgil is worth at least £8m," said Mjallby.
"I'd like him to stay with Celtic, especially in the summer when they try again for the Champions League.
"I can see Virgil playing in one of Europe's top leagues.
"I would be surprised if he doesn't play for a top team in the future.
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