8. Park Ji-Sung
Jon Super/AP/Press Association ImagesPark Ji-Sung was well-renowned throughout his early career for his boundless energy and enthusiasm and nearly endless stamina, being branded 'Three Lungs Park' for his workload. His time at United was definitely the highlight of his career, winning a glut of titles and being a trusted lieutenant of Sir Alex Ferguson in the big games to shackle his more illustrious opponents, even if his first team opportunities were comparatively limited. He had a very good work ethic in the centre of midfield and would never shirk a challenge, and he also developed a reputation for scoring in the big games, particularly against Arsenal. As a result of his commitment and that invaluable knack, he became a fans' favourite during his time at the club, and while he may have lacked a certain talent in skills, he could blunt other stars with his tackling and tracking back. But then when he left for QPR in 2012, things rapidly went downhill, as he only made a handful of appearances during an injury-hit two year spell with the club, which induced his premature retirement earlier this year. This seems so far away from the glory he tasted at United.