The Suns spearhead became emotional in the rooms following Thursday night's 14.19 (103) to 12.8 (80) win over St Kilda at Marvel Stadium.
After being on the verge of re-signing with Gold Coast earlier in the season, King is expected to request a move to Hawthorn.
In a post-game interview, King replied "it could be" when asked if he thought it was his last game for the Suns.
"Whatever happens over the next couple of months, I love this group of blokes," King told the Seven Network.
"It's been really special."
Hardwick admitted "we probably know which way it's going".
"He was obviously quite emotional, so it might possibly be his last game," the Suns coach said.
"We're not quite exactly sure.
"Once I know, you guys will know, and he'll make his thoughts clear."
Although King will be a huge loss, having kicked 315 goals across 143 games for Gold Coast, the Suns do have young forward talent coming through.
Jed Walter has emerged strongly this year with 33 goals and earned a bumper contract extension, while the towering Ethan Read is improving.
Hardwick still has high hopes for former No.1 draft pick Jamarra Ugle-Hagan, even though he only played three games in his first season with the Suns.
"We've got some some younger players, we're really excited about Read," Hardwick said.
"We're really excited about Walter.
"We've got Jamarra, who has had a bit of a pivot year. He'll be better when he comes back.
"But we probably need another experienced player, so if there's any experienced forward out there that wants to come to our footy club, give me a call."
After winning a historic elimination final last year, the Suns have crumbled under the weight of expectation this season.
Early premiership favourites Gold Coast, who gave club stalwart Nick Holman a perfect send-off with the win over the Saints, went on a 10-game losing streak that knocked them out of finals contention to finish with a disappointing 9-13 record.
"It has been a challenging year," Hardwick said.
"We fell short of expectation. We accept that.
"We are accountable and responsible for that, so we'll get better.
"It's going to be a quick bounce.
"This year will be the making of our footy club."