Indeed, Sinclair feels West Ham's mindset is slightly below what is needed when they approach a game offering teams less respect than they would the likes of Arsenal or Liverpool.
He feels that was certainly the case during two of the Irons' defeats at Upton Park so far this term.
Sinclair told Sky Sports News on Monday morning: "Offensively, very good. Defensively, at time they can be good. The biggest problem for me is, when they feel they’re the better team, they’re not quite at it.
"You need to respect the opposition and I’m not sure they went into the Bournemouth or Leicester games with those kind of thoughts. The defending was poor and they tried to play out of situations that were too dangerous and risky."
It's an interesting theorem from Sinclair, who is hit and miss with his analysis but, when it comes to his former clubs, is usually on the ball.
Here, it's hard to disagree with the former West Ham man. From Slaven Bilic to Dimitri Payet, the Hammers squad may well have approached Bournemouth and Leicester City with less determination than the Arsenal, Liverpool and Manchester City games.
Tactically, it also likely has plenty to do with the absence of an Alex Song type playmaker in midfield, meaning West Ham can't necessarily control games at home rather than hit teams on the break.