The hole on Gold Coast's list going into this season was its lack of depth in key defenders.

In captain Steven May and sidekick Rory Thompson, the SUNS have a tandem as good as most in the competition.

But who would step in if one – or both – got injured?

That man is Jack Leslie.

Now in his fourth season at the club, the 22-year-old has played the past four games and is starting to look at home.

GALLERY: Captains and Coaches Press Conference in Shanghai

When May missed matches against Adelaide and North Melbourne with a hamstring strain – and with Thompson already missing with a quad injury - Leslie was forced to play as the sole key defender.

He improved so much that even with both back to play Port Adelaide in Shanghai on Sunday, the 11-gamer is likely to keep his spot.

"I had a lot to do with him in the pre-season," May told the media earlier this week.

"I explained to him that he can play in our starting back six, he doesn't have to wait for an injury to myself or Rory, and maybe he thought that was the case.

"It was a blessing in disguise with us going out, because he had to step up and play like a 100-game defender and take on the best.

"I remember when I was a young back, that's what happened to me.

"Nathan Bock went out of the side and I had bags (of goals) kicked on me because of the lack of experience, but it helped fast-track my development, and I think you've seen that with Jack."

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Leslie performed well against Adelaide skipper Taylor Walker despite an avalanche of inside 50s against his team, and not all of Kangaroo Ben Brown's six goals were Leslie's responsibility the next week.

"The confidence of your teammates is an important thing," Leslie said.

"As Rocket (coach Rodney Eade) always says, you can't go and buy confidence from the shop, you've got to manufacture it, and that definitely helps.

Leslie is 197cm and 98kg and has improved his mobility noticeably over the past 12 months.

"He looks like he's got a cool head now and his voice on the weekend was outstanding," May said.

"Just in two weeks with me being on the sidelines, he's improved.

"I'm excited for what he's got to bring to the club."