Conor Glass says Oisin Mullin must make Aussie rules his sole focus if he is to make a career for himself in the AFL.
Derryman Glass, who spent four-and-a-half years with Hawthorn, played 21 times for the club before ending his time Down Under last year.
It was announced last week that 2020 Young Footballer of the Year Mullin has signed for Geelong.
"One piece of advice was just give everything you can, don't be going in half-hearted," said Glass at the launch of the AIB Club Championships.
"If you go in with the mindset of, ‘I'll give it a crack for a couple of years and if it doesn't work out, and then I'll come back to the GAA’, you're not going to succeed out there.
"You have to go out with the sole focus of ‘I'm going out there to make it, going out there to play for 10 or 15 years’. He'll have the guidance of Zach Tuohy and Mark O'Connor out there, which will benefit him in the long run as well.
"He's one of the best defenders in Ireland before he left. He's still a young age as well and he's played against the best players in Ireland, so he has that experience of playing at the highest level. If he can transition, learn new skills out there, there's no reason why he can't be one of the top level players in the AFL."
Glass admitted that part of him does miss the lifestyle he had in Australia.
"Waking up when it's three degrees here and it's dark at 4pm or 5pm, it can be not that nice," he said.
"The lifestyle of some of my friends out there, they're probably at the beach. I miss that aspect of it, but then you have the aspect of having your family and friends around. You can pick bits and pieces, but I don't regret my decision at all."
Oisin mullin will be a star in the AFL. Physique / fitness / teak tough. @GeelongCats look after him and you will have one of the greatest imports the game has seen 👍
— Conor.mortimer (😷)⚽️ (@Conmort) November 11, 2021
He also said that the Covid-19 pandemic has made life tougher for Irish players in the AFL.
"I think Conor Nash only got home for the first time in two or three years. It would have been tough in that regard," Glass said.
"The list sizes have decreased because of Covid. Some of the international rookie spots have been taken away. The pathway is a bit harder, but it shouldn't limit the impact that the Irish players have out there."
The AIB GAA Club Championships and AIB Camogie Club Championships, will see AIB celebrating #TheToughest players of all: those who don't quit, who keep going and persevere no matter what. These characteristics define the players who come back year after year and show up for their club when it matters most.