Barcelona's attempt to appoint Xavi Hernandez as coach was held up on Friday over his Al Sadd release clause, with Xavi and Barca considering splitting the payment to complete the deal.
Al Sadd announced in a statement earlier on Friday that Barca had agreed to pay the clause in Xavi's contract, which is reportedly set at around 5 million euros ($5.8 million).
But while Barcelona remain confident Xavi will be their new coach, the club disputed that a deal had been agreed and were yet to confirm the Spaniard's appointment almost five hours later.
A source close to negotiations told AFP on Friday discussions were still ongoing over the clause and one possibility was Xavi and Barcelona would each contribute to the payment.
"Al Sadd have said it is official but Barca have not. Let's wait," said Barca's interim coach Sergi Barjuan, who is expected to be in charge for the La Liga game against Celta Vigo on Saturday.
Al Sadd published photos on social media of Xavi saying goodbye to the club's players and staff.
Al Sadd chief executive Turki Al-Ali had earlier said in a statement: "The Al Sadd administration has agreed on Xavi's move to Barcelona after the payment of the release clause stipulated in the contract.
"We've agreed on cooperation with Barcelona in the future. Xavi is an important part of Al-Sadd's history and we wish him success."
Barcelona sent vice-president Rafa Yuste and director of football Mateu Alemany to Doha for talks on Wednesday as the club sought to replace the sacked Ronald Koeman.
But Al-Ali insisted Al Sadd were "committed to keeping Xavi" and they appear to be holding their ground in the negotiations.
"Xavi informed us a few days ago of his desire to go to Barcelona at this particular time, because of the critical stage his hometown club is going through, and we understand this and decided not to stand in his way," Turki Al-Ali added in his statement on Friday.
- Weakened by Messi's departure -
Xavi faces a formidable challenge after Barcelona let Lionel Messi join Paris Saint-Germain in the summer, having posted debts of 1.35 billion euros.
The Spaniard left Camp Nou to play for Al Sadd in 2015, after making 767 appearances for the Catalan club, which included winning eight La Liga titles and four Champions Leagues.
Xavi came through Barca's La Masia academy and his passing style was seen as the embodiment of Pep Guardiola's "tiki-taka" team that won the treble in 2009. He is widely considered to be one of Barcelona's greatest ever players.
There are high hopes Xavi can draw on his incredible playing career to revive Barcelona, who currently sit ninth in La Liga, with concerns growing they might not finish in the top four.
In Europe, Barca face a fight even to qualify for the knock-out stages of the Champions League while any rebuild will have to be carried out on a shoestring budget as the club struggles to deal with the debts it partly built up paying Messi's wages.
Xavi will also be charged with improving the team's style of play, which was a key criticism during the tenure of Koeman, another Barca former player.
"Barca's style is genuine and non-negotiable," said president Joan Laporta last week. "I don't think it has been lost, but it has moved away a bit. We want to recover the essences.
"Football evolves and the coaches are more versatile. At Barca, we like to have the ball. Johan Cruyff taught us that. We want spectacular football, but to win."
Laporta had been sceptical about Xavi's experience as a coach after only two years in charge of Al Sadd and decided to continue with Koeman, despite plans to sack the Dutchman both in the summer and the October international break.
But Laporta said poor results and deteriorating performances made the situation "unsustainable".
"I am very excited to go home," said Xavi after what appeared to be his final game in charge of Al Sadd on Wednesday.
"And even more to be Barcelona coach, which has a lot of responsibility, but I am very excited and motivated."