The Gold Coast SUNS have been forced to make two changes to its initial team named to play Port Adelaide on Saturday night.

Gary Ablett has been ruled out of the match after failing to complete a fitness test during training at Metricon Stadium on Thursday evening.

Ablett injured his hamstring in the SUNS' Round 20 match against Fremantle at Domain Stadium.

General Manager - Football Operations Marcus Ashcroft said Ablett did all he could to get himself up for the game.

"Gaz gave himself the best opportunity to play this weekend, but unfortunately at training this evening he simply could not reach the speed required to be passed fit to play this weekend," Ashcroft said.

Ablett will be replaced in the selected side by Mitch Hallahan.

Meanwhile, Jack Bowes injured his hamstring during the session and has also been ruled out of the match. He will be replaced by Brad Scheer who was brought into the squad following Hallahan's inclusion.

Alex Sexton has been added to the squad as an emergency.