Pisi has received rave reviews for his performances since he arrived at Franklin's Gardens after the World Cup, scoring three tries in 22 appearances and winning the Travis Perkins man of the match award in the Aviva Premiership Rugby win over Bath.
The centre is up against Steve Mafi, Nick Evans, Mike Brown and Chris Robshaw for the gong, which will be handed out at the 2012 RPA Players' Awards on May 23rd.
The Samoan international was stunned to receive the news of his inclusion in the short-list.
"I am truly shocked and humbled that I've been nominated by my fellow peers," he said. "It's been a blessing to have had this opportunity to play in the Aviva Premiership. I hope that my performance and that of the team gets us to the final at Twickenham and we can win it for Saints."
Saints players have won the RPA Players' Player of the Year on two previous occasions - Pat Lam in 2000 and Bruce Reihana in 2004.