The former Manchester City and West Ham United winger is unsure as to why the 24-year-old has not featured more regularly for the Eagles, while suggesting that he believes Alan Pardew's decision to let him leave the club may be misguided.
Recent reports, such as those in the Guardian, suggest that Bristol City have had an undisclosed offer, believed to be valued at £6million, for Gayle accepted - as is often the case with former players, Sinclair has taken to Twitter to react to this news:
Gayle has mostly featured as a substitute since his switch from Peterborough United two seasons ago, but this has not stopped him from being among the goals for the Selhurst Park outfit.
Indeed, he has been top scorer (based on goals in all competitions) in both seasons he's spent with the club - eight in 2013-14 and 10 in 2014-15 - despite starting just 19 games in the past two years.
Sinclair suggests a move to Bristol City and the Ashton Gate Stadium - where he will undoubtedly receive regular game time - will see him thrive. The former City midfielder believes his finishing ability will make him a huge success in the Championship.