O'Neill has made no secret of his desire to one day play outside of the A-League and test himself at Europe.

After three impressive seasons with the Sky Blues, the 24-year-old has less than six months left to run on his current deal.

According to recent reports, Aston Villa, QPR and Rangers are among those interested in luring the talented Australian to the UK.

O'Neill is weighing up whether to leave Sydney FC at the end of the 2018/2019 season after winning four trophies with the club.

"I have aspirations, like anyone else in Australia, to play at the highest level and overseas," he told FTBL.

"Both myself and Sydney FC, and as a club they’ve been brilliant in terms of talking about that and they realize that’s what I want to do. But they also want to support me and help me as much as possible.

"But maybe not yet – there’s still a lot of football to be played, a lot of scenarios to play out.

"The biggest thing for me is I have the support of the club, I have the support of my family and friends that I will make the correct decision moving forward that ultimately helps me achieve what I want to achieve and where I want to play.

"It’s a good position to be in because lads that have been in this situation don’t have the support and the actual guidance to make the right decision, and it is a big decision because I’m 24 now.

"We’ve been so lucky to have the success we’ve had at Sydney FC and I feel that the next part of my career, and the next part of my life is trying to play at the highest level possible.

"Whatever the situation or the scenario that plays out, me and Sydney FC are committed to making sure the best outcome happens for club and player."

Sydney FC are unsurpisingly keen for O'Neill to stay with them next season.

The central midfielder has missed just three A-League games in the past two and a half campaigns.

"Brandon is a fantastic asset for our club and has been instrumental in the club's success these last few seasons," Club CEO Danny Townsend said.

"We will be doing everything we can to keep him at Sydney FC."

O'Neill has been transformed as a player after arriving at the Sky Blues in 2015 from Perth Glory searching for regular game-time.

The West Australian found it at Allianz Stadium, thriving under the coaching of Graham Arnold and becoming an integral part of the side that won two premierships, a grand final and an FFA Cup.

The 24-year-old remains indebted to Sydney FC.

"I’ve said this to so many people but Sydney is my footballing home and forever will be," he said.

"I was born in Perth and raised in Perth, and my family and friends are still over there, but in terms of my career and what’s happen in the four years I’ve been here this will forever be my home.

"I’d love to travel and see a bit of the world and then finish my football career here because it’s the best club in the A-League, it’s the best club in Australia to be part of and I have no intention of ever playing for any other A-League club because of what they’ve offered me and what I’ve been able to do here.

"It’s a big decision that I’ve got to make this year… I’ll make sure I’ll make the right one and everyone will be happy."