Lloris has struggled in recent weeks and question marks have emerged over whether the Tottenham captain deserves to remain the club’s number one goalkeeper.
His performances have been inconsistent and there have been calls for Tottenham to even look for a new number one in the market in the summer.
Sinclair feels the Frenchman is no longer a world-class goalkeeper and he has seen him commit too any mistakes in recent weeks in terms of flapping at balls and with his shot-stopping skills.
The ex-Three Lions winger said on talkSPORT: “Not for me [he is not world class].
“I have been to a couple of games where I have seen him flap at balls, he has had really quite straights shots at him, and he got one hand to it.
“His wrists and hands are too weak, I think he got his angles wrong in goal as well. You look at the Manchester City goals he conceded last week.
“I think he has been poor.”
Sinclair feels Lloris’ goalkeeping abilities are on the decline and he believes Hart could not do any worse if he gets a chance to replace the Frenchman in the Spurs goal at the moment.
“For me, I think he is waning on his abilities or whether it’s just a bit of form that has gone out of the window and it is going to come back – I don’t know.
“But if Joe Hart is training well, I would not hesitate to put him in because at the moment from what I have seen, he couldn’t do any worse.”
Lloris has been at Tottenham since 2012 and has made more than 350 appearances for the club.