The 31-year-old has been at Stamford Bridge since 2017. He has won the Premier League, FA Cup, Champions League, Europa League, Uefa Super Cup and FIFA Club World Cup during his time at the club.
Alonso joined Wanderers in 2010 from Real Madrid. He went on to play 46 times and score five goals for the club over the next three seasons.
He moved to Italian side Fiorentina in the summer of 2013 as moved to the continent despite the offer of a new contract. He scored five goals in 84 games for the club.
He spent the second half of the 2013/14 campaign on loan at Sunderland. He played 20 times in that time.
Despite a trophy-laden time at Chelsea, it appears Alonso's time at Stamford Bridge is poised to end. He has 29 goals and 211 appearances to his name since joining the London side in 2017.
The Daily Mail now reports that Alonso is close to moving to Barcelona now. It is reported that the former Bolton defender has said his farewell's to Chelsea's staff at the club's Cobham training complex.
The move comes following Chelsea's acquisition of Marc Cucurella from fellow Premier League side Brighton & Hove Albion. Cucurella has switched sides for a reported 62m transfer fee.
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