Former Liverpool defender believes that John Terry's vote for the PFA Player of the Year was tactical.
The Chelsea defender revealed that he had picked Liverpool's Philippe Coutinho on Instagram, with no club able to choose one of their own players.
Eden Hazard is favourite for the honour, but Carragher told the Daily Mail that Terry would have encouraged the Chelsea dressing room to avoid selecting other leading contenders Harry Kane and David de Gea.
Carragher said: "How do I know? I did exactly the same thing in 2006 when Steven Gerrard won. I was Liverpool's PFA representative back then.
"I made it clear that, for Stevie to win, nobody should vote for Thierry Henry or Frank Lampard. You might think that's unfair but it is the same in every dressing room."
Hazard, De Dea, Kane and Coutinho were also nominated for Young Player of the Year.