GEELONG’S injury woes could be worse than first thought, with fears Gary Ablett could miss up to six weeks and the club’s two best key defenders facing late-season returns.

The Cats on Wednesday hinted that Ablett was edging towards an AFL return from a hamstring injury but still refused to put a definitive time frame on the two-time Brownlow Medal winner’s comeback.

“Gary’s going well ... (he) ran again (on Wednesday) and his running sessions have been completed pretty well,” club physiotherapist Mark Young said.

“He’ll join in football later this week and from there he shouldn’t be too far away.”

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The 33-year-old injured his hamstring in the final quarter of the Round 3 clash against West Coast. It followed a similar injury which slowed him in the latter stages of the pre- season.

But Herald Sun reporter Jon Ralph said Ablett’s hamstring injury is likely to keep him out for around five weeks.

“Take it as read: This is not a three-weeker. This could easily push to four or five or six weeks,” Ralph told Fox Sports News’ AFL Tonight.

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Geelong's Gary Ablett in Round 3. Source: AAP

“Ablett’s injury wasn’t just a little pull-up, he jagged that hamstring good and proper.

“Given his previous hamstring injuries, I don’t think anyone would be surprised if he missed potentially five weeks.”

The 2-2 Cats have struggled with a lengthy injury list at the start of the season.

While Cory Gregson’s foot sprain diagnosis was positive, the club revealed this week that luckless defender Lachie Henderson underwent another bout of knee surgery on Tuesday.

It was Henderson’s third operation on his right knee since the end of last season and there is no definitive timeline for his return.

Ralph said the club is preparing for Henderson to return “later this year”.

“I don’t think they really have any idea how he is going to come up,” Ralph said.

“He was really close to getting back with a knee injury and then it required more surgery.”

Harry Taylor injured his foot in Round 1. Source: AAP

Key defender Harry Taylor remains out indefinitely with a plantar fascia issue that was aggravated in Round 1.

Ralph said Taylor is still at least one month away from a return.

“He’s out of a moon boot, only just, he’s at least walking — or what the club has described as ‘loading’ — but he is yet to start running, yet alone progress to full training,” Ralph said.

“So essentially, five weeks on from that injury, he’s effectively lost all of that summer of conditioning.

“A return around the halfway mark of the season would be more realistic.”

Nakia Cockatoo (knee), Cam Guthrie (ankle) and Lincoln McCarthy (quad) are among the other Geelong players currently unavailable.

— with AAP