The ex-Australia youth international spent three years with Northampton before returning to Australia this year. He won his Mariners deal after successful preseason trials.
"Pedj is a player that weâ€™ve been keeping our eye on for some time and we're suitably convinced and confident that he has a lot to offer at this level," said Mariners Executive Chairman Lyall Gorman.
"Pedj is regarded by many as the best player in the NSW Premier League and, mindful of the success that weâ€™ve had previously when recruiting from this league with the likes of Mile Jedinak and Matt Simon, weâ€™re hoping to have landed another success story in Pedj.
"We're confident that Pedj's character and ability, coupled with his determination to succeed in the Hyundai A-League will make him a fantastic and vital addition to our playing stocks for our Premiership defence and we're delighted to have officially welcomed him to our club for what we believe will be another very successful season."
"Since returning, I've trained with a few clubs and experienced some of the setups on offer around the country and, for me, the Mariners was head and shoulders above the rest, particularly in regards to the team spirit and morale here, which is among the best Iâ€™ve ever been apart of.
"I'm excited to be playing alongside each of my new team-mates here on the Central Coast and I'm confident, as the entire playing group is, that we have a squad capable of lifting some silverware this season and continuing the fine history that this club has set in previous years."