GREATER Western Sydney's 80th debutant, Jeremy Finlayson, believes he can have an impact on his team's fortunes this year after admitting he wasted the first two years of his AFL career.

Finlayson has been picked for tonight's crucial clash against Geelong at Spotless Stadium after Zac Williams was forced to drop out of the selected side due to a tight hamstring.

The 21-year-old has been in impressive form in his six NEAFL games this year, averaging 27.8 possessions as a running defender and wingman, while the team has struggled to win just one game thanks to a long injury list.

Match preview: Greater Western Sydney v Geelong

Taken with selection 85 at the 2014 NAB AFL draft two years after he moved to Sydney on a GWS scholarship from the tiny country town of Culcairn, near Albury, Finlayson initially struggled to adapt to life as a professional footballer.

But the Giants academy product finally got his mindset right last year and won the GWS NEAFL development award, after starring in the club's reserves premiership team.

"My first two years I didn’t have the belief that I could play at AFL level, I just wasn't up to the standard," he told AFL.com.au.

"I was getting frustrated because people back home would ask me why I wasn't playing, but I knew I had to do the work and my time would come.

"It took a couple of years for me to build myself up, but I believe in myself a lot more now.

"It really helped me when the players kept telling me I could make it and it gave me the desire to go after it, so it's been two years I kind of wasted, but it's been my dream to play in the AFL and it's finally come true."

Finlayson played a key role for the Giants during last year's NEAFL finals series but copped a three-game suspension after a heavy clash with Sydney's Zak Jones, meaning his start to 2017 was delayed.

Despite the setback, he tried to use his ban and the inspiration he got from winning the Giants' first ever flag to fuel his pre-season training.

"It was a long pre-season and extremely frustrating, especially because I never intended to take him high, but I think it gave me a bit of an edge," he said.

"It gave me an extra three weeks to work on my fitness and that was the main target I needed to work on.

"Being a new club, it didn't matter if it was in the AFL or the NEAFL, winning that first flag was a huge driver and it's something I'll always cherish."