“He tried replacing [Luis] Suarez with four players really, when you take into consideration [Adam] Lallana, [Mario] Balotelli, [Rickie] Lambert and [Fabio] Borini.
“Those four players have amalgamated nine goals between them.
“The manager technically and tactically fallen way behind what I expected from him this season.
“Liverpool are a shadow of the team from last season and Brendan Rodgers has to take responsibility for that, and also the players.”
And Quinn questioned whether Rodgers can transform Liverpool into title challengers again next season, despite taking the club to within two points of the championship last season.
“Is he the man to take Liverpool forward to the next step and win the Premier League," Quinn added. "Can he really improve Liverpool now? You can’t just blame Suarez’s departure.
“They played okay against Chelsea in the League Cup semi-final, but against Aston Villa [FA Cup semi-final] I don’t even think the Liverpool fans could believe what they were seeing.”
Speculation surrounding Rodgers’ future at Anfield has intensified in recent weeks and Quinn claimed Borussia Dortmund boss Jurgen Klopp would be a suitable replacement.
The 47-year-old announced he will leave the Bundesliga club at the end of the season and German football expert Raf Honigstein believes he would find it hard to turn Liverpool down.
“The natural replacement to me is a guy who has been involved in the Champions League, Jurgen Klopp," said Quinn.
“He’s very passionate and he loves Liverpool. I’m not saying that is going to get him the job but he is a guy who plays a similar type of football and has more experience than Brendan Rodgers.
“If Rodgers is going to stay next season then he has to improve dramatically.”