Sheldon, 22, was a regular member of the 2009 team that went all the way to the second week of the finals, but after some injury problems early in 2010 has battled for a berth since.
But after coach Michael Voss gave him another look-in against Essendon in round eight, Sheldon has worked his hardest to retain his spot.
He is playing arguably the hardest position in the game, the position where the ball often flies from the midfield to the big marking targets like skipper Jonathan Brown.
Sheldon might not see much of the ball, but it's his job to lock it in the Lions' forward line and ensure the opposition doesn't stream out and start a counter attack.
He has now played the past nine matches and said continuity and confidence in his body was the major difference in making an impact this season.
"In 2009 I had limited preparation but I had a few good weeks of training before I came into the side and I was fit and managed to hold my spot and play good footy," he said.
"Next year (2010) I had a good pre-season but hurt my hammy and had a few back problems coming into the season and once I got behind I battled to get back to where I needed to be.
"Just the minimal level to play AFL footy I wasn't around the mark. And I couldn't get back in good enough form to be selected for a start.
"I was lucky enough to stay on this year, had a good pre-season and had to earn my spot back which I've done, and now I'm just trying to stay in there and do my role."
Sheldon started the season in defence in the reserves, but had to take a change of tact if he wanted a recall to the top team.
The Lions' back six was settled in the early part of the season with Daniel Merrett, Joel Patfull and Jed Adcock all fit and playing well.
"I thought I had to do something different to get in the team so they moved me to the forward line in reserves and the opportunity came up in the seniors," Sheldon said.
"It's a hard spot. I've got massive respect for guys like (Steve) Johnson from Geelong, Cyril Rioli, that play that role to the best it can be played. At times it can become no man's land because you're caught in the middle and it's going over your head all the time. I think I'm learning it and getting the hang of it.
Sheldon was drafted by the Lions as a 17-year-old and has now played 33 games.
He said he wants to stay at the club long term and help the other young players bring the Lions "back on top where we should be".
"History shows that sides that go through this stuff (losing seasons) and stay as a group come good, and long term success comes off the back of that."
Michael Whiting covers Brisbane Lions news for afl.com.au. Follow him on Twitter: @mike_whiting
