Sinclair, now assistant manager of Lancaster City, was an instant hero to Hammers fans after scoring both goals in a 2-2 draw with Everton on his debut in 1998 following a move from Queens Park Rangers.
In a career spanning five years at Upton Park, Tricky Trev - as he affectionately became known on the terraces - scored another 35 goals in 177 appearances, the most he made at any one club throughout his career. He forged an almost telepathic understanding with another Hammers hero, Paolo Di Canio, and many of the club's best goals during that period involved the entertaining duo. None more so than Sinclair's brilliant assist for the fiery Italian's goal of the season against Wimbledon (below).
But if the Manchester-born winger's West Ham career started with a bang, it ended with a whimper. The club was relegated with what remains a Premier League record 42 points under Glenn Roeder and, forced to cut costs, West Ham accepted a £3.3million bid for the player from his boyhood club Manchester City.
The former England international's departure disappointed some Hammers fans who had hoped Sinclair would stick around to help the club fight for instant promotion back to the big time.
But while many fans had assumed Sinclair, now 42, had been angling for a move back "home" the player turned pundit has taken to Twitter to reveal the truth.
Responding to a question from a fan on the social networking site, West Ham's former number eight said he was angry with how the club was being run.
He said: "I didn't wanna leave for any specific club! I was just really p****d off with the Rio (Ferdinand), Frank (Lampard) and Harry (Redknapp) departures!"
Irons chairman Terence Brown had sold Ferdinand to Leeds for a then record £18 million before later dispensing with the services of Redknapp. Redknapp's nephew Lampard was next out of the door for £11 million to London rivals Chelsea and, following relegation, Sinclair decided enough as enough.
The fans' favourite sill holds the Hammers in high regard, but turning his attentions to next week's clash between two of his former clubs as West Ham travel to QPR, Sinclair added it would be like "watching my 2 best mates having a fight (but) QPR really need to fight back this time."