THE ONUS is on St Kilda's younger players to fill the "void" left by retired stalwarts Nick Riewoldt and Leigh Montagna, star midfielder Seb Ross says.

Riewoldt is third on the all-time list for longest-serving captains in VFL/AFL history, having held the mantle for 220 games, while Montagna lined up in 287 matches in a highly consistent career that started when he was drafted at No.37 in 2001. 

Ross was the Saints' runaway best and fairest this year after taking his game to a new level and he expected his more youthful teammates to follow suit in 2018 when asked where the club's improvement would come from. 

"It will definitely be from our younger group, I reckon. You can already see a shift in the guys at training," Ross said. 

"We had two legends of the footy club leave last year in 'Joey' (Montagna) and 'Rooey' (Riewoldt), and those guys were such strong leaders. 

"Now there's a void there and there's guys that really have to step into it. I think young guys like (Jade) Gresham, JB (Jack Billings), Blake Acres, Lukey Dunstan, those guys have already had terrific starts to their pre-seasons, so I really expect those guys to flourish this year." 

Ross was in the leadership group for the first time in 2017, along with Dylan Roberton. 

The defender spent time in hospital earlier this week after suffering a ruptured testicle in a game of indoor cricket. 

The 26-year-old father of three was struck by a tennis ball that was taped up so it would move in the air.

"It was just a normal tennis ball but taped up with the electrical tape. The reason people probably think it was a cricket ball was because (captain) Jarryn Geary had the great idea, if you could tape the whole ball, but just tape one half of it with a bit more tape, you actually wouldn't know which way the ball was going to swing, and Robbo didn't," Ross said. 

Ross spoke at Arden Street alongside Essendon recruit Devon Smith for the launch of Flick Footy Max, a game that helps reduce stress.