Barcelona will be unable to retire Lionel Messi's iconic No.10 shirt following his emotional farewell from the club unless they opt to permanently give up a valuable slot in the senior team quota, it has been revealed. 

Spanish FA rules state LaLiga teams must assign their 25-man squads the numbers 1 to 25 for each league campaign.

Goalkeepers either wear 1, 13 or 25 while on the rare occasion of reserve players brought into the first team, they are able to take on from 26 to 50.