GEELONG will send promising young defender Jackson Thurlow for scans on Monday after he was stretchered from the field with an apparent serious knee injury in the third quarter of Saturday's NAB Challenge match against Essendon at Deakin Reserve in Shepparton.

The Cats' doctors could not confirm the severity of damage to Thurlow's right knee after his knee buckled underneath him in a marking contest with former teammate Mitch Brown.

Geelong assistant coach James Rahilly said the incident did not look good for the 21-year-old, but the club was holding out hope for a positive outcome.

WATCH THE HIGHLIGHTS: Essendon v Geelong

"The docs have had a little bit of a look but they can’t confirm anything yet," Rahilly said after the game.

"He hasn’t had much of a go, just fingers crossed he is all right and he can be part of that back line that we need.

"He has had a great pre-season, he would have been a good chance for round one if that’s the case. His rebound, his ball use, has been really important for us, so we just cross our fingers."

The news is better for Tom Lonergan and Lachie Henderson.

Lonergan appeared to injure his ankle in the first half of the match, while Henderson was seen applying ice to his left knee in the third term.

"They just got knocks and we didn’t think it was worth them going back on the ground to push through it … just a precautionary thing," Rahilly said.

Rahilly, who is in charge of Geelong's midfield group with Matthew Knights, was pleased with Geelong's improved defensive efforts against Essendon; a marked difference from a disappointing outing against Collingwood last week.

The Cats kept the young Bombers goalless in the first half and let through just three majors for the game. It was a far cry from the 21 goals the Magpies booted last week.

"Collingwood kicked something like 200 goals (sic) against us last week, so defensively it was a little bit better and that was the main focus going into the game," Rahilly said.

"We transitioned a little bit better. Especially in the first half I thought it was quite good and that was the main part of the game that we were pleased with."

The news of Paul Couch's passing hit the Cats' camp hard.

"I don't actually know how many people knew about it, but obviously our hearts and thoughts go out to Geraldine and the family," Rahilly said.

"He was not only a champion of the footy club, but just a great character, so it’s a tragic loss for the Geelong family.

"I'm a Warrnambool boy, like Paul as well. I know the family and know his wife. I would catch up with Paul now and again. It's a very sad loss and he will be missed."

The Cats are unlikely to make many changes for next Saturday's showdown with Fremantle in the west as they ramp up their preparations for round one.

Patrick Dangerfield, Zac Smith and Henderson are all set to line up again, while Geelong may recall Daniel Menzel, who was rested for the game against the Bombers, pending the medical staff's advice.