Real Madrid goalkeeper Iker Casillas’ seemingly imminent transfer to FC Porto is in danger of collapse, according to the Spanish publication Marca.

Yesterday evening, the player’s representatives were in discussions with Porto officials and reached an agreement that appeared to finalize the Spain international’s transfer to the Portuguese side.

Both Real Madrid and Porto had already agreed to terms for the veteran goalkeeper, where no money would be paid for his transfer; and Casillas had accepted a payment reduction from the two years he had remaining on his contract with Madrid

The only issue that was left to be resolved was the remaining money Real Madrid needed to pay their team captain for the final two years of his deal.

However, as things stand now, the entire transfer is on the verge of completely breaking down.

According to Marca, Casillas wants the money from the two remaining years of his Real Madrid contract to be paid in gross, not in net; and the Spanish club is balking at that demand.

Also, a problem has surfaced regarding the payment of Portuguese taxes, which are not as demanding as Spain’s fiscal system.

And finally, the involvement of third party negotiators has also complicated what was seemingly a transfer which was satisfactory to everyone involved.

Time is running out and Casillas is expected to report for his medical and the first day of Real Madrid training on Friday morning. This is something the club and player were keen to avoid.

Before this latest obstacle was placed in the way, the club’s plan was to officially announce the transfer today with Casillas being given a hero’s sending off at the Santiago Bernabeu on Friday or (at the latest) Saturday.

But now the entire move is in jeopardy.

The delay also means Real Madrid officials will have to continue holding off on their ‘all-out’ assault on Manchester United goalkeeper David de Gea.

Earlier today, it was learned the Spanish side had been preparing a mega-money offer for the United player.

However, with Casillas’ future in limbo – again – Real Madrid officials will have to put those plans on hold – at least until this fiasco reaches is settled.