FC Barcelona goalkeeper Marc-Andre ter Stegen on Tuesday had an operation on his back to try and solve the problems that have affected him in the lumbar region.

FC Barcelona confirmed the operation in a statement, explaining the operation took place in Bordeaux and explaining that the "evolution" of the injury would "mark his availability."

The operation has stirred controversy not only over Ter Stegen's fitness, but also because of Barcelona's fragile financial situation, which has so far prevented the club from registering summer signings Joan Garcia and Marcus Rashford for La Liga due to financial fair play restrictions.

The club either needs to find new income or lower its wage bill to include Rashford and Garcia in the squad, and if Ter Stegen is out of action for over four months, Barca will be able to use 80 percent of his salary to cover the wages of the new arrivals - as the club did last season when Thomas Christensen suffered an ankle injury.

The 33-year-old appeared to challenge the club last week when he announced the operation, adding that he expected to be out of action for just three months, which would mean Barcelona would be unable to use this option to inscribe its new signings.

The situation could lead to Barcelona passing Ter Stegen's medical report to the Spanish Football Federation (RFEF) which has a committee of experts that would decide the time of the goalkeeper's probable absence.