Roberton, who arrived at St Kilda from Fremantle as a delisted free agent last November, has played every game this season in a defensive group that has worked hard to cover injuries to key players.
In round three he won a career-high 27 possessions against Greater Western Sydney in arguably the best of his 40 AFL games, and he shapes as a key cog in the back six against a potent Essendon on Saturday night.
With Sean Dempster (hand) and James Gwilt (knee) sidelined, Roberton said it would be important for the Saints backmen to help each other out against the Bombers.
Lack of height, he said, was no excuse.
"We need to fight ferociously and defend as hard as we can," Roberton told AFL.com.au.
"Even though we are undersized, we need to fight hard and help each other out when we can, come off our man and help a teammate who may be one-on-one or isolated.
"We try not to use the lack of height as an excuse. We're still holding our own."
St Kilda is ranked sixth in the AFL for points against so far this season and is yet to concede 100 points in losses to Gold Coast and Richmond and last Saturday's win over GWS.
Roberton, who stands 194cm, has mostly been used us as a third or fourth tall option, averaging 20 disposals and four marks a game.
Highlighting his willingness to help teammates, he has taken marks backing into contests, which is an area of his game that wasn't apparent at Fremantle. ?
"When you're playing on those smalls who get up the ground, you can tell if they're not going to get used or they're not in a dangerous space so you try and get back to help," he said.
"It's pretty much the same role I had [at Fremantle] … just defend hard, defend first and win the footy, then attack when it's time and get involved in the play."
Roberton, who grew up in Melbourne and represented Dandenong in the TAC Cup, has enjoyed returning to his home town after three seasons with Fremantle.
His first experience with St Kilda was in Colorado as part of the club's pre-season training camp and he said the bonding on that trip was valuable, helping him get established quickly with his new teammates.
While it has appeared to be an easy transition for the 21-year-old, he remains cautious after playing 10 games with Fremantle last season and being an emergency nine times.
On current evidence, he is on track to match those 10 games and turn the nine emergency roles into starting spots.
"I wouldn't say I'm a guaranteed start and I'm not comfortable with my position," he said.
"I'm definitely not relaxed and knowing that I'm going to get picked every week, so I'm just trying to do the things that will keep me in the team."
Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan
