ST KILDA defender Nathan Wright is pushing to prove his fitness ahead of the Saints' opening NAB Challenge match as he eyes a full-time role across half-back this season.

Wright, who suffered a torn left calf one month ago, will likely miss the Saints' intra-club match this Saturday, but he is expected to be available for the first pre-season game, against the Brisbane Lions on February 28.

The 21-year-old, who has otherwise enjoyed his strongest pre-season yet, is ready to showcase a more attacking game after three years honing his shutdown traits.

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"For this year, my biggest focus has been getting involved more in offence," Wright told  

"In my first couple of years I tried to nail down my defence and stop my man and I feel comfortable having that part of my game down pat now.

"This year I've put a big focus on getting 15-20 possessions every game and helping rebound the footy coming out of defensive 50.

"With my improved fitness, hopefully that will help me run out games better and get those possessions on a weekly basis."

After winning 22 possessions against Greater Western Sydney on debut in 2013, Wright hasn't had more than 14 touches in his 14 games since, averaging 9.9 touches in 2014.

But after running three personal best times in the Saints' 2km time trials over the summer, he is confident he can become an influential player under a more attacking St Kilda game plan. 

The strong-bodied half-back, who turned 21 on Monday, said the calf setback wouldn't strip him of his pre-season gains seven weeks out from round one. 

"It's been about one month now, so I'll get back into full training this week," he said.

"It was a pretty random injury, it was the last kick of the session and I went to follow through and felt it go.

"Up until then the pre-season was all pretty positive … this was my first pre-season where I was injury free and the body was all good.

"Hopefully I'll train fully this week and then be right for round one of the NAB Challenge."

Wright knows he will still face stiff competition for selection across half-back, with Jimmy Webster, Cameron Shenton, Shane Savage and Dylan Roberton all eyeing the same post.

The long-term plan for Wright, however, is to follow the path of teammate Jack Newnes, who has bulked up sufficiently to play an inside midfield role this year.

"As I get a bit older, my body gets a bit bigger and I keep improving my fitness, then hopefully I can have more of a midfield or wing type role," Wright said.

"Last year I had issues with my weight where I came back too heavy, so this year I tried to keep it pretty controlled and I had a stricter diet.

"I think that's really helped me." 

Nathan Wright is a $239,000 defender in NAB AFL Fantasy this year. Create and fill your AFL Fantasy Classic league by March 2 to win a free AFL Live pass.