Robbie Gray leaves the field after his 250th match against Gold Coast in round 14, 2021. Picture: AFL Photos

PORT Adelaide star Robbie Gray is set to extend his career into a 16th season despite an untimely knee injury that will keep him on the sidelines until the final round of this year.

Gray's 250th match ended prematurely on Saturday when he was substituted at half-time of Port's win over Gold Coast.

Follow-up scans revealed the torn medial ligament in his left knee required surgery.

The Power expect Gray, one of their most important players and a three-time best and fairest, to be on the sidelines for eight weeks.

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There are nine rounds remaining in 2021, meaning any setback in the 33-year-old's recovery could put him at risk of missing the start of finals.

Gray is out of contract at season's end.

Port football manager Chris Davies says he has "no doubt" the forward will be at the club in 2022, regardless of whether he hits a contract clause related to playing a certain number of games in 2021.

"Robbie's start of the year has been sufficiently good to suggest he should be around for next year," Davies told reporters in Adelaide.

"In fairness to both Robbie and the club, there was never any doubt that whatever happens ... would be a mutual decision."

Port, who sit fifth on the ladder, host sixth-placed Sydney in Saturday's crunch clash at Adelaide Oval.

The timing of the game could yet be tweaked as the League plots a path around a growing COVID-19 cluster in Sydney.

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Defender Lachie Jones is set to be out of action for a month, having suffered a hamstring injury during the Power's victory over the Suns.

Gray and Jones join fellow key players Zak Butters, Xavier Duursma and Orazio Fantasia on a long injury list.

"It's going to be a challenge for us, no doubt," Davies said, confirming Butters, Duursma and Fantasia would likely spend at least another week on the sidelines.

"The cupboard is becoming increasingly bare but, at the same time, there's some guys who have played some good AFL footy and will get a chance now."

Davies admitted Gray was "disappointed, as you can imagine".

"It wasn't a great end to his 250th game. His challenge now will be to get right before the finals," he said.