When we've had players in the past, I've always had a small part of me thinking that if the offer was big enough there could be an argument to sell them if it was re-invested to strengthen wisely.
Van Dijk changes that whole perspective for me though. He is the first players I've ever classed as completely priceless.
Not only because he the best CB I've ever seen, or that he is just so ridiculously good, but no Van Dijk means Robertson, TAA, Matip, Lovren, Gomez games all suffer, he's that influential.
You heard Robertson say it not that long ago, he keeps him right, he can play his game as he knows Virgil is never out of position. The confidence that gives to a full back in invaluable. If you don't have that as a full back, you're indecisive.
I've honesty never seen a single players have as much influence on a whole team.