The Hammers fan favourite is leaving the London Stadium to take up a coaching opportunity overseas.
The 30-year-old progressed through the youth ranks and made 121 first team appearances as a midfielder between 2008 and 2014 before having a stint at Peterborough United, but his playing career was sadly cut short due to injury (The Independent).
Collison returned to the East London club two years ago to coach the Under-16s but, earlier this week, the West Ham website announced that he would be departing his role, describing it as "a unique opportunity overseas".
Here is what the Hammers fan favourite wrote on the social media platform:
A number of West Ham fans wished him all the best and also expressed sadness at seeing him go:
NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO— Chris Scull (@cjscull) 13 June 2019
Good luck Jack. ⚒⚒⚒— Ben Shephard (@benshephard) 14 June 2019
Good luck in all you do Jack - it was so good knowing you and working with you over the years. ⚒— Steve Bacon (@onesteviebacon) 13 June 2019
You’ll always be family to us ⚒⚒⚒— Lena Starr Princess of Spades (@LenaStarrXXX) 13 June 2019
Good luck Jack. Hope all goes well in your new job. We will miss you. Was hoping I'd finally get to meet you (missed you at Isla's match) Have some photos I'd hope you'd sign. All the best ⚒— Susan Clark (@claretbluesue) 13 June 2019
Excited for you - but super sad to see you go! The supply at West Ham’s gonna go up without you there though that’s for sure— Kelly Somers (@KellySomers) 13 June 2019
Good luck Jack, hope it goes well for you and the family. Thanks for giving Ted and all the the other kids an enjoyable start to football ⚽️ Hopefully see you back at the hammers in the big seat one day⚒#COYI— Gibbo (@Gibbothehammer) 13 June 2019
Good luck mate you are a diamond wish nothing but the best for you and family— Bertie brayley (@bertiebrayley) 13 June 2019
According to BBC Sport, Collison has accepted a coaching role in the United States at Atlanta, the current MLS champions, who are managed by former Crystal Palace and Inter Milan boss Frank de Boer.
West Ham have replaced Collison with another fan favourite in Kevin Keen, who came through the Hammers' youth ranks in the 1980s, made close to 300 first-team appearances, and then enjoyed a nine-year spell between 2002 and 2011 as a youth, reserve and first team coach at the club (official website).
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