The napkin which famously launched Lionel Messi’s Barcelona career as a 13-year-old will be auctioned off in March with a starting price of £300,000 ($382,150). With Messi’s father, Jorge, beginning to doubt Barça’s commitment to his son in 2000, the club’s director of football at the time, Carles Rexach, hastily scrambled together an agreement on a napkin. – Stream on ESPN+: LaLiga, Bundesliga, more (U.S.) It was signed by Rexach,…