Roos joint vice-captain Jarrod O’Brien (broken toe) will replace TAC Cup-bound teenager Lachy Dawson in the Kangaroos’ best 21 against South Warrnambool on Saturday night.

Kangaroos coach Matt Dunn said the pair played similar roles as ball-winning inside midfielders.

The second-year mentor said he was rapt Dawson was picked to make his Greater Western Victoria Rebels debut.

“It’s terrific. He’s fully deserving,” Dunn said.

“Lachy’s been good the last three weeks in the senior side and he’s gotten better every week.

“He’s so good at the clearances and is strong around the contest and brings others into the game.”

Dunn is backing another promising teenager to handle the ocassion of a big game under lights, bringing in debutant Rory Gill.

He said Gill, who will play wing and half-forward, was a success story out of the Roos’ decision to submit an under 16 side in the Hampden league Sunday competition this season.

“We’ve been looking at him since round one,” Dunn said.

“It was a good opportunity to bring him in.”

South Warrnambool has also backed youth, selecting Ethan Harvey to replace the unavailable James Edmonds.

Port Fairy has made four changes for its clash against Portland at Hanlon Park.

Xavier McCartney (ankle), Kurt Smith (overseas), Adam McCosh (omitted) and Josh Dwyer (omitted) make way for Sam Rudolph, Cam Pevitt, Jordan Scott and Eddie Purvis.

Seagulls coach Brett Evans said ruckman McCosh was unlucky to lose his spot.

“Sandy Robinson is very fit,” he said.

“He can do the majority of it and we thought we have more versatility on the bench.

“We have two or three guys who can give him a chop out throughout the game and Adam is still in our plans but we thought we’d try something different.”

Portland has lost ruckman Ben Malcolm and ball winner Jake Edwards but brought in Cam Mather and Jay Moody among four changes.

Cobden coach Levi Dare will return from suspension against Terang Mortlake along with midfielder Paul Pekin and youngster Sam Gilbett.

Trent Reed (TAC Cup), Jake Evans (calf) and Dom Dare (omitted) will miss.

The Bloods made one forced change with Scott Carlin returning to TAC Cup duties.

Joel Crawley is his replacement.