Cornes was limited to only nine appearances for the Power this season, as a result of the club's rebuilding process under first-year coach Matthew Primus.
Accepting he wasn't part of Primus' plans going forward, the 31-year-old announced his retirement in August and said 'goodbye' in a farewell game against Collingwood at AAMI Stadium in round 20.
The 239-game veteran displayed solid form when given an opportunity, prompting suggestions he should seek to continue his career at another club.
Speculation is rife the dual All Australian will be reunited with Power premiership coach and current Giants assistant coach Mark Williams next year.
There are also reports retired ruckman Dean Brogan, who played his final game for Port Adelaide against Melbourne last weekend, has been offered a playing and/or coaching role alongside Williams and Kevin Sheedy.
Cassisi said he wouldn't begrudge his long-time teammates an opportunity to extend their careers with the AFL's 18th team.
"I'd feel fine about it," Cassisi said.
"Chad and 'Broges' have been great servants of our football club. They've given the club every bit of what they could deliver, and we can't question that.
"If they decide they've got another year in them and there's an opportunity there, I think they'd be silly not to take it."
It remains unclear whether Cornes would join GWS as one of up to 16 uncontracted players, which would result in compensation for Port Adelaide, or under another draft concession afforded to the club.
The Giants are only able to take one uncontracted player from each club (with the exception of Gold Coast) unless a club consents to releasing additional players.
