Gysberts suffered the injury during Casey’s six-point win over Coburg Tigers in the VFL on Saturday.
Football manager Josh Mahoney said the club expected Gysberts to miss four to six weeks.
“Unfortunately, Jordan hurt his ankle during the second quarter of Casey’s game against Coburg on the weekend,” Mahoney said.
“This is disappointing for Jordan, as he has been improving each week at VFL level, and had started that game particularly well with his tackling pressure.”
Forward Ricky Petterd (leg) and defender James Strauss (concussion) face fitness tests after missing the opening round of the season.
Mahoney said Petterd was still in the mix for Melbourne’s clash against the West Coast Eagles at Patersons Stadium on Saturday.
“Ricky was close to selection last week,” he said.
“If he gets through a full week of training this week, he will be available for selection for our game in Perth.”
Key Demons Col Sylvia (back) and Liam Jurrah (wrist) will miss another three matches each.
“Col has been increasing his movement each day, and he is on track to resume in three weeks,” Mahoney said.
“Liam is still continuing to build his conditioning base, and will begin football training in the next couple of weeks.”
Tall forward Lucas Cook will miss the next two matches with a groin injury, and ruckman Jake Spencer (knee) is only a week away from resuming.
Versatile small Neville Jetta is out indefinitely with an ankle injury.
Ruckman Max Gawn is out for the season with a knee injury, and youngsters Michael Evans and Rory Taggert are out indefinitely with back injuries.
Round two injury list
Lucas Cook (groin) - 2 weeks
Michael Evans (back) - indefinite
Max Gawn (knee) - season
Jordan Gysberts (ankle) - 4-6 weeks
Neville Jetta (ankle) - indefinite
Liam Jurrah (wrist) - 3 weeks
Ricky Petterd (leg) - test
Jake Spencer (knee) - 1 week
James Strauss (concussion) - test
Colin Sylvia (back) - 3 weeks
Rory Taggert (back) - indefinite
