Ilkay Gundogan, Barcelona's latest acquisition, is reportedly free to leave the club if he is not registered by Sunday.
Gundogan opted to leave Manchester City after seven years after winning the treble under former Barcelona manager Pep Guardiola last season.
Despite obvious financial issues, Barcelona moved quickly to sign the Germany international on a free transfer after his contract with the Etihad expired.
Forbes believes that a clause in Gundogan's contract allows him to go for free if the club fails to register him before their season opener against Getafe.
Barcelona are thought to pay Gundogan £8.6 million a year on a two-year contract, but he will still be paid for this year even if he does not register in time.
In a similar circumstance to last season, Barcelona are racing against the clock to register their new arrivals in time for the start of the La Liga season.
Robert Lewandowski and three other new faces were just registered on the eve of the new season a year ago, and history may repeat itself this season.
With the start of the new season only a few days away, only 13 players have registered, including Franck Kessie and Ousmane Dembele.
The imminent sales of Kessie and Dembele are expected to pay Gundogan's registration, so president Joan Laporta hopes they may be finalised this week.
Kessie is expected to join Saudi Arabia, while Dembele is expected to return to his native France and join Ligue 1 winners Paris Saint-Germain.
Inigo Martinez and Oriol Romeu are the two other significant new additions at Camp Nou this summer, but there are no indications of comparable terms in their contracts, which could result in the same consequence.
Although a clause in Gundogan's contract states that he can leave for free, the German midfielder spoke highly of the club when signing.
The 32-year-old stated that joining the Spanish giants was a 'dream move,' so even if the worst-case scenario arises, he may not be able to force his way out of the club.
Gundogan was instrumental in Man City winning the triple last season, netting four goals in the final weeks of the season to help the club steal the title from opponents Arsenal.
His two brilliant volleys in the FA Cup final helped City defeat rivals Manchester United at Wembley, and he also played in City's Champions League final victory over Inter Milan in Istanbul.
Gundogan is joining a club that, despite serious financial issues, believes it is on its way back to the top.
Last season, Xavi's team won La Liga, but they were duped in the cups, particularly the Champions League, where they were eliminated in the group stage.
For more Sports updates please follow us on Twitter