South Warrnambool export Cooper Atchison, who is in year 12, will play with his younger brother Flynn Atchison.

Year 11 trio Fraser Marris (South Warrnambool), Patrick Rea (Warrnambool) and Toby Jennings (Portland) will also feature in the decider against St Bede's College at Trevor Barker Oval.

AFL draft combine invitee Isaac Wareham, who hails from Terang Mortlake, will miss with a knee injury.

Cooper Atchison, who is playing for Ballarat league club Redan, said it was extra special to play alongside his brother.

"I played with him in juniors for most of the years so it's always good fun," he said.

Atchison, 18, is combining senior football with Redan - the club he joined at the start of the 2019 season - with school commitments.

He played five games as a bottom-age prospect for St Pat's last year and has established himself in its midfield this season.

But the benefits of boarding have stemmed beyond the football field.

"It's been a good experience. School work, I am getting a lot more done up here as well so I reckon I've probably benefitted from it a lot," Atchison said.

Marris, 17, moved to St Patrick's at the start of year 10 19 months ago.

The decision has helped fast-track his football - he's already played 12 NAB League games for Greater Western Victoria Rebels this year as a bottom-age small forward prospect.

"I was just hoping to get a couple of games being one of the younger boys," Marris said.

"I am hoping to finish the year off well. Hopefully we can win our wildcard round with the Rebels and also go into finals with South (Warrnambool).

"I am hoping to get a decent pre-season and try-out again for the Rebels next year and see how I go.

"I'll be hoping to get a few more midfield minutes but I am happy to play anywhere."

Marris said he had enjoyed donning the St Pat's guernsey too.

"It is pretty exciting (being a year 11 player)," he said.

"Everyone is welcoming and with all the older boys we've got some nice leaders in the group, so it will be good to run out with them on Wednesday."

Have you signed up to The Standard's daily newsletter and breaking news emails? You can register below and make sure you are up to date with everything that's happening in the south-west.