Cornes is one of the most decorated players to have played for the Power in their short AFL history, but the premiership player and dual All-Australian has struggled with form and fitness in recent years.
The 31-year-old played 14 straight games last season before being dropped for brother Kane's 200th milestone match in Primus' first outing as caretaker coach against the Western Bulldogs in Darwin in round 16.
He was sent back to SANFL for the first time in more than a decade and played two games with Glenelg before suffering a season-ending broken finger.
Cornes returned to pre-season training early, keen to re-establish his place in the side but conceded it would be a difficult task given the club's youth-first policy on selection.
"Matty Primus and I had a good chat and he was really honest with me. We've been great friends for a few years now, so I'm sure it was as tough a conversation for him as it was for me, but he was really honest with me," Cornes told Radio station Fiveaa.
"The club's stance is to play young players this year. They're aiming for their next premiership and are building towards that and I fully understand where he's coming from.
"If there's a young kid playing as well as I am and training as well as I am the young kid will get the go, but if I'm training better than them, playing better than them and doing all the right things off the field then I'll get a go."
Cornes has been dogged by injury in the past three seasons.
The former vice-captain has battled finger and calf injuries, as well as a nagging knee complaint which he said had threatened to derail his pre-season this year.
"Prior to Christmas, my knee was playing up a bit and I wasn't really able to train the way I would've liked," he said.
"After Christmas it really settled down. Now, my body is feeling as good as it has in a while and I've been training pretty well over the last month."
After several seasons in the midfield, a battle-weary Cornes returned to defence last year with the aim of prolonging his career.
