Haynes didn't believe him. He'd been drafted with pick number seven in 2011 as a midfielder who could drift forward, and his fighting weight was barely 78kg.

But Sheedy is one of the AFL's great geniuses and his prediction has proven to be much nearer the mark than Haynes ever imagined.

In two years he put on 13kg and was sent down back to learn the art of defence, playing alongside one of the club's best backman in Phil Davis.

A couple of years further on and Haynes is now an established member of a GWS back six tasked with the most unenviable job in football – shutting down a destructive Sydney forward line.

There's Lance Franklin of course, fresh from a seven-goal haul against Richmond last start.

Ben McGlynn managed five in that game and Gary Rohan grabbed four goals himself. Throw in Kurt Tippett who'll enjoy lengthy periods resting up forward in the qualifying final and you have the league's most potent attack.

"One person will get the main job, we'll try and play as a back six to nullify their forward six and try to back in our system to beat their's," Haynes said.

"Any team would be worried about him [Franklin]. We've got Phil Davis and Adam Tomlinson as well alongside me, so I think we'll all share a bit of time on him. I've tried to grow my game, not just become a tall defender, a small defender, but trying to be an overall good defender. I'm really thriving on that challenge."

Davis will likely spend the most time on Franklin, freeing up Haynes to play his usual gliding back-line role where he has established himself as one of the AFL's best intercept markers.

He and teammate Heath Shaw have played an important role in the Giants' groundbreaking year, nullifying opposition attacks before launching counter thrusts of their own. It wasn't always so easy for Haynes though.

When he began his back-line apprenticeship under the urgings of Sheedy, he was powerless to stop the endless floggings that plagued the club in its embryonic phase

"In my first year I probably didn't deserve a game to be honest because I was so young and raw," Haynes said. "Normally when you get drafted to a club you have to earn your stripes to play AFL games, sometimes a year, sometimes two years.

"To get thrown in I guess was a good experience but it was definitely tough. A lot of those boys that were in that draft are now 23, 24 years old. Along with the guys that came here like Callan Ward and Phil Davis and the additions of Mummy [Shane Mumford] and Heath Shaw, if you put all [of] them together it hasn't surprised me that we've made finals this year.

"We're not going to forget those big losses we had and we don't take any wins for granted now because of the past we've had."

Should Haynes and the GWS back six nullify the Swans' forward line, they might just earn a home preliminary final in two weeks.

If Franklin and co are allowed to run amok though, the Giants will be back at Spotless Stadium next week with either Adelaide or North Melbourne coming to town.