EXPERIENCED Greater Western Sydney midfielder Tom Scully has suffered a pre-season setback, with an ankle injury to keep him sidelined until at least late in the NAB Challenge.

Scully, who missed the final five weeks of 2014 with a knee injury, strained an ankle late in a scratch match at training a fortnight ago.

Giants coach Leon Cameron told AFL.com.au the club would give Scully four weeks to recover, and the Giants expect the 23-year-old to be ready to play against St Kilda in round one at Etihad Stadium.

Scully was back running on a treadmill on Friday as the Giants played their final intra-club practice match ahead of the NAB Challenge.

"His fitness is not an issue," Cameron said. "He's tracking really well and we'll definitely go the four weeks with him."

Scully was in good form before injury hit last year and was looking to build on that showing in 2015, his sixth season since he made his debut in round one, 2010.

He told AFL.com.au in mid-February that it was time for him to improve further in 2015.

"I feel I'm at a stage now, coming into my sixth year, my body's used to it so it's a matter of me playing consistent football," Scully said.

Scully, who has played 86 games, is entering the fourth year of his six-year contract with the Giants. He has played 55 games with the club, and has been fiercely defended at all times by Cameron in the face of external criticism.

Cameron said it was important to get Scully right because the Giants were aware of the importance of having their mature players fit and available throughout the season.

He said playing too many first and second-year players at once put too much pressure on both the experienced and inexperienced players.

The Giants play their final NAB Challenge match against the Sydney Swans on March 22 before taking on St Kilda in round one.

Tom Scully is a $440,000 midfielder in NAB AFL Fantasy this year. Create and fill your AFL Fantasy Classic league by March 2 to win a free AFL Live pass.