Manchester United will have to spend big if they are to sign Ajax goalkeeper Jasper Cillessen, with coach Frank de Boer claiming the Netherlands international's price is increasing by the week.
Unsettled United keeper David de Gea's future remains up in the air but he is expected to join Real Madrid before the transfer window shuts, and Cillessen has reportedly emerged as countryman Van Gaal's number one choice to fill the void at Old Trafford.
But Ajax will not part ways with the 26-year-old without a fight, having missed out on replacement keepers Maarten Stekelenburg and Wojciech Szczesny, who joined Southampton and Roma, respectively, on loan.
"Man United will have to pay huge price for Cillessen," De Boer is quoted as saying in the Mirror.
"Let it be clear that we are going to take a really strong attitude and we will fight against him leaving at this stage.
"Why? Because we have seen all our three alternatives go out of sight and it gets harder and harder to find a decent replacement.
"To make it clear, Jasper is getting more expensive by the week, although there are certain figures that we can't turn down."
