Van Dijk has been on the books of Celtic since 2013 when he moved from Dutch club Groningen, and he has gone on to establish himself as one of the best players in the Scottish Premiership.
According to The Daily Mail, Premier League clubs Everton, Southampton, Arsenal and Sunderland are all interested in signing the 23-year-old in the summer transfer window.
Collins has admitted that it may be tough to keep hold of the highly-rated centre-back and has conceded that it will be tough to replace him.
"Virgil's got two years to go [on his contract]," the 47-year-old told BBC Scotland. "I think he is an outstanding player and it's a pleasure for me to coach him. I'm hoping and praying we can keep him for another year."
"I think he has the talent to play for any team,” added Collins. “There’s no doubt for me he can play at the top level.
"I think there would be many clubs out there who would love to have him. He makes it look so easy. When the day comes when he leaves he will be very difficult to replace.”
Collins’s comments about Van Dijk show just how much Celtic depend on him, and it will indeed be tough for the Bhoys to replace him.
However, Celtic can take relief in the fact that the Dutchman has two more years on his contract, which means that they can get some good money if he does decide to leave in the summer.
The key will be to spend that money wisely and sign the right replacement. No footballer is irreplaceable - unless he is Lionel Messi or Cristiano Ronaldo - and if the Scottish giants do scout the European market, then they will get a suitable replacement for Van Dijk.
It will also be important for Celtic to decide on Van Dijk’s future on way or the other as soon as possible in the summer to give themselves time to find a suitable replacement.