Charlie Ballard in action for Gold Coast against St Kilda in R5, 2022. Picture: AFL Photos

GOLD Coast's patchwork backline has taken another hit, with the Suns expected to confirm a season-ending knee injury for young defender Charlie Ballard.

Ballard left the Gabba late in the third quarter of Saturday night's loss to Brisbane after his right knee buckled awkwardly after being inadvertently hit by teammate Sam Collins.

The Suns will confirm a medial collateral ligament injury for the intercepting defender, which will sideline him for the final four rounds.

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Ballard will join a list of unavailable defenders that already includes Lachie Weller (knee), Wil Powell (ankle) and Connor Budarick (knee).

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Terrible luck as important Sun leaves field with knee injury

Lachie Weller has left the field with an apparent knee injury after this incident

Veteran Brandon Ellis, who has played wing most of the season, said the backline was running "a little thin", but was confident the Suns had the depth to cover.

"I might have to spend a bit more time down there the rest of the season, which I'm happy to do," Ellis told AFL.com.au.

"I've played a lot of my career at half-back, so I know what I'm doing.

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"The next person that comes in knows what they have to do, play their role and play our system."

Ballard has had a fantastic season, ranked second behind Paddy McCartin (61) for most intercept marks with 58.

One option at Stuart Dew's disposal to cover Ballard would be for versatile Jy Farrar to play as the third tall defender alongside Collins and Caleb Graham, allowing Ellis or Oleg Markov to play a more aggressive role.

Gold Coast's Jy Farrar evades Lincoln McCarthy of Brisbane in R19, 2022. Picture: AFL Photos

"A bit of continuity would be nice, but that's footy, it's imperfect, injuries happen and you've got to deal with it," the two-time premiership Tiger said.

"Our backline has a lot of depth.

"Oleg has got very good leg speed, he's a good ball user, he's good below his knees and above his head. We've got options."

Gold Coast's finals chances all-but disappeared following the 17-point loss to the Lions, but Ellis said they had to knuckle down against West Coast at Metricon Stadium on Sunday because "you never know what can happen".

"We definitely want to win as many games as we can … but we've just got to focus on this week."