The classy centre-back is hanging up his boots after Barcelona play Almeria at the Nou Camp on Saturday night, following a trophy-laden second spell with the Catalan giants.
The 35-year-old initially left his boyhood club for United in 2004, and was part of the squad that won the Premier League and Champions League in 2007/08.
After making his debut against Crewe Alexandra in the League Cup, he made 23 appearances for the Reds in total, scoring twice, before heading back to La Liga in the summer of 2008.
Pique has won over 30 trophies during his career, including eight domestic title wins and three Champions League triumphs - two of the latter were with Barcelona at the expense of Sir Alex Ferguson's United in the final.