ST KILDA'S senior players have been told they can still be crucial members of the club's push towards its next premiership.

There are five Saints aged over 30 on the list, with captain Nick Riewoldt (32) and midfielder Leigh Montagna (31) both contracted until the end of next season. 

Important defender Sean Dempster (31) announced a one-year contract extension on Thursday, ensuring he will be part of a finals push in 2016 after enjoying another impressive season that has him in contention for All Australian selection. 

The future is less certain for Sam Fisher (33) and Adam Schneider (31), but coach Alan Richardson said a strong senior core was vital for the club as it prepared for next season. 

"You look at any footy club and more often than not the better players are the senior players," Richardson said. 

"The Bulldogs have had an outstanding year and (Matthew) Boyd and (Bob) Murphy will often be in their best group. 

"The young players coming through have in many ways stimulated our more senior players and they're starting to see the wheel is turning in the other direction and the journey is a positive one.

"I've made sure they have no illusions they're going to be a part of it … they're going to be significant members of what's coming."

Richardson said the Saints had been looking to next year for about four weeks at the selection table, with veteran Farren Ray, who hasn't played for the past three matches, one casualty.

Although keen to keep a senior core at his disposal, Richardson said tough decisions were inevitable.

"Farren is a player who clearly could still play some pretty good footy for us, but we need to have a look at other players," Richardson said. 

"It's always a balance. Those guys are really important to us and we don't need to go and recruit experience.

"But there's always that discussion at the end of the year. If (recruiting and list manager) Tony Elshaug and his crew say we need a certain amount of picks, then that might mean one or two might to go.

"There's a lot of water to go under the bridge before we know what that looks like."

The Saints look set to bring in midfielder Darren Minchington for his third game this season to face North Melbourne in Hobart, with Daniel McKenzie (concussion) and Jack Lonie (leg) both sidelined.   

American ruckman Jason Holmes is unlikely to be unveiled this week, with Billy Longer more likely to come in to face star Kangaroo Todd Goldstein and either replace – or work in tandem with – Tom Hickey.  

"Billy Longer has been really strong for us. He was a bit sore last week, but he's back in the mix to come in this week," Richardson said.

"He (Goldstein) is a fairly complete footballer on the outside as well, so you've got to be able to go with him.

"That's the challenge and we're certainly contemplating two rucks this week."

Young half-forward Jack Sinclair has been cleared to play after suffering a head knock and a shoulder injury against Fremantle in round 19 but midfielder Luke Dunstan will miss one more week with a calf injury.