Gundogan could provide a short-term answer to these problems and would not require a settling in period.

Manager Pep Guardiola did not want Gundogan to leave City last year, but the club were unwilling to offer the German midfielder the contract length he wanted.

After joining City from Borussia Dortmund for a reported £20m in 2016, Gundogan made 304 appearances for the club, scoring 60 goals.

During seven years at Etihad Stadium he won 14 trophies – five Premier League titles, one Champions League, two FA Cups, four Carabao Cups and two Community Shields.Media caption,

Monday Night Club: Daniel Storey and Chris Sutton on Ilkay Gundogan

Why are Barca having trouble registering players?

In 2013, La Liga clubs agreed to specific economic rules aimed at guaranteeing the sustainability of the competition.

It means that all clubs have a limit on player expenditure, essentially not being able to spend more on the playing squad than they earn in a season.

This is known as their ‘squad cost limit’ and is calculated by deducting a club’s projected non-sporting expenses, such as salaries and agent fees, and outstanding payments owed to other clubs, from their expected revenues for the season.