MADRID (AP) The deadline arrived, but the announcement never did.

In a surreal ending to the transfer window in Spain, the much-anticipated move of Manchester United goalkeeper David de Gea to Real Madrid never materialized. The clubs reportedly struck a deal, but the expected announcement never came, apparently because the paperwork wasn't submitted on time.

Real Madrid and United had finally appeared to reach an agreement on the transfer on Monday after talks that dragged on for several weeks, but local media said the clubs failed to register the new contract with the Spanish league offices before midnight local time.

More from FoxSports

So much for British punctuality. Or was it a failure by the Spanish club, which had to convince goalkeeper Keylor Navas to make the move to Manchester as part exchange?

Neither club officially commented by early Tuesday, and nobody was taking the blame for the bizarre breakdown that quickly became the object of fan derision and mockery.

With the teams and La Liga staying quiet, speculation quickly spread as to why the deal fell through. There was talk about United taking too long to send in the paperwork, and even about technical difficulties with the file that contained the contract. Some also talked about a possible calculated delay by Real Madrid to try to save money, as De Gea is on the final year of his contract with United and can leave on a free transfer at season's end if he's not sold.

But reports said it was the move of Navas to England that delayed the deal. The agreement on De Gea was finalized, but reaching an understanding with the Costa Rican goalkeeper was more complicated.

Spanish newspaper Marca said Navas, who had been reluctant to leave Real Madrid, arrived at the Santiago Bernabeu with his agent to finalize details of the contract with United just minutes before the midnight deadline. They reportedly wanted some changes made and they couldn't be finalized on time.

Real Madrid fans had been praising Navas recently, while many criticized the club's decision to try to sign De Gea. The crowd at the Santiago Bernabeu on Saturday loudly chanted Navas' name after he saved a penalty in the 5-0 rout of Real Betis in the Spanish league.

It was unclear whether the clubs could or would appeal to league authorities or FIFA in an attempt to push the deal through. The English transfer window remained open through Tuesday.

If it can't be done, it will create a difficult situation for the De Gea, who could be forced to return to United despite having been dropped from the team by manager Louis van Gaal as the talks dragged on. Van Gaal had said the Spanish goalkeeper had his heart set on a move back to his hometown.

---

Tales Azzoni on Twitter: http://twitter.com/tazzoni