According to reports, Barcelona will not be able to retire Lionel Messi's number 10 jersey. 

Messi officially left Barcelona on Tuesday night to join Paris Saint-Germain. He agreed to a lucrative two-year contract with an option to extend it by another year. 

According to the Daily Mail, La Liga teams are required by the Spanish federation to assign each member of their squad a number from 1 to 25 before the start of each league season. Goalkeepers wear shirts with the numbers 1, 13, or 25. 

Any additional reserve players may take up any number between 26 and 50. 

However, if Barcelona decides to retire Messi's number 10, they will have to give up a first-team spot. This means that instead of having 25 players available for the matchday squad, the team will only have 24. 

This is due to the fact that first-team squads must be registered with the Spanish football governing body with numbers ranging from 1 to 25. 

This isn't the first time a Spanish club has retired a jersey number. After the death of their defender Daniel Jarque, Espanyol of Catalonia retired a jersey number in 2009. Following the death of the defender, the number 21 jersey was retired. 

It should also be noted that when FC Barcelona lost Luis Suarez to Atletico Madrid last season, they did not retire the number 9 shirt, despite fan calls to do so. Martin Braithwaite, a new player, received the jersey number. Some argue that he does not deserve the number, but that is the reality of Spanish football rules. 

Messi began his career at Barcelona wearing jersey numbers 30 and 19, before receiving the famous number 10 for the 2008/2009 season, following Ronaldinho's departure to AC Milan. 

The bigger debate among pundits and football fans is "who is the player who deserves to wear the Legendary number 10?"