Xavi, ahead of the Barca presidential debate between Laporta and Victor Font, made the claim, insisting the deal had been cleared by LaLiga.
He asserted: "Leo was signed. In January 2023, after becoming world champion, we got in touch and he told me he was excited about coming back, and I saw it.
"We talked until March and I told him, well, when you give me the OK I'll tell the president because I see it as a footballing opportunity.
"The president started negotiating the contract with Leo 's father and we had the green light from LaLiga , but it was the president who threw everything off."
While Laporta has rejected Xavi's claims, Alemany, who was a director at Barca at the time, insisted: "Xavi is right. They told us they had him.
"Xavi is right."