St Kilda champion Nick Riewoldt has unveiled a list of players who he identifies as the most irreplaceable for their team.

Although some may be the obvious selection, some listed are simply the players Riewoldt believe fit best in the system of their respected club. When these types of players miss games, it creates issues for coaches, players and fans.

Following a stellar finals series, Riewoldt believes West Coast's Jeremy McGovern is extremely pivotal for the structure of Adam Simpson's side.

"We saw in the Grand Final, if he is not aggressive in leaving his man they don't intercept that ball at half-back and Dom Sheed isn't having a shot at goal at the other end." Riewoldt said for Fox Footy.

McGovern's ability to read the play and set up his side defensively can be compared to the work of Richmond defender Dylan Grimes, who Riewoldt believes is the Tigers' most important player.

Grimes has the ability to play on both smalls and talls, he builds comfort within Richmond's back six, ensuring he'll get the job done against the game's most dangerous forwards so players like Alex Rance can get off the chain (although Grimes now becomes even more important following Rance's season-ending injury).

Being a defender is never the most attractive role, but for Grimes it's all about limiting scoreboard pressure, and it comes natural for him.

The same can be said about Kangaroos defender Robbie Tarrant, who has been getting the well-earned recognition of late, successfully limiting each side's number one forward week in week out, "he is such a well balanced defender", Riewoldt said.

Geelong's Mark Blicavs is one of the competition's most versatile footballers. He allows the Cats to shuffle him in any position desirable. Blicavs can play across the wing, down back or pinch hit in the ruck - the epitome of the modern day footballer.

Riewoldt listed three spearhead forwards as their club's most important players, with Sydney's Lance Franklin, Hawthorn's Jack Gunston and Greater Western Sydney's Jeremy Cameron all featuring.

Franklin is the obvious one, given he is the Swans' best player and without him they struggle to reach big heights scoring-wise. There isn't anyone jumping out to replace him as Sydney's next big forward.

Both Cameron and Gunston have kicked upwards of 40 goals per season several times in their career; their ability in the air, forward pressure and all-round goal sense has fans praying for them to feature every week.

Collingwood's Jordan De Goey has the ability to break open a game within minutes. The Magpies have several areas and players they can lean on for goals, but trying to stop an in-form De Goey inside 50 is quickly becoming one of the toughest jobs in football.

Following his maiden All-Australian, Adelaide's Rory Laird comes into season 2019 as one of the top small defenders in the league. The Crows are at their best when Laird has the footy, his run, pace and skills can rarely be faulted.

"They go coast-to-coast better than any team because the ball ends up in his hands so often and he is just such a good user." Riewoldt states the Crows are at their very best when Laird is continuously firing.

The impact Devon Smith had on Essendon last year has brought some hope to the red and black army. Smith is a tackling machine who applies immediate pressure every time the ball's in his area.

"In terms of culturally what he did for that group last year down the stretch was enormous... It inspires your teammates and it becomes a reference point for your coaches." Riewoldt said about Smith's importance to the Bombers.

Finally, the former Saint noted the importance of premier rucks Max Gawn and Brodie Grundy. It's not just about giving first use to their midfielders, but around the ground they force teams to change game-styles just by being present.

Riewoldt believes "the introduction of the six-six-six rule makes them even more valuable".