St Kilda coach Ross Lyon has questioned the AFL's contentious substitute rule in the wake of his side's thumping win over Fremantle on Friday night.

First-year Saint Tobie Travaglia was named as the sub for the Saints' clash with Fremantle but was never activated. When asked about the decision, Lyon offered up a strong defence for Travaglia and shifted the conversation toward the broader flaws in the system.

Vision of Travaglia showed the young prospect looking frustrated having to sit side-line while his team embarrassed the travelling Dockers side in a prime time Friday night slot.

Yet, Lyon made it clear that the issue ran far deeper than just when or whether a young player gets minutes.

"I didn't see the visible frustration, I didn't see that. Any AFL player worth their soul wants to be in it," he said.

"I suppose the wider issue is that all AFL clubs said 'let's get rid of the sub', right? Because there's enough stress in the game without putting people under the spotlight.

"There's a lot that is involved in the sub and a lot of complexities that aren't obvious when you go 'oh, we've got sub.' So I think that's the wider issue, rather than worrying about Tobie or 'sub them early or sub them late, don't use them.'

"We're in the business of winning AFL games, right? So everything was going really well, so yeah, we didn't use Tobie.

"He's a great kid and his parents were there after the game and they were really positive. If you look at it, he's played three out of six games... You know, James Sicily got two games in his fourth year?

"So I mean, this expectation that you get drafted and just play immediately, we talk about the Geelong school of footy like, there's a lot of them that don't play their first or second years, so it's just given the context I think he's ahead of the curve, he's played three out of the first six."

The sub rule has long been a source of debate and Lyon's frustration with the rule reflects a wider sentiment among clubs, many of which reportedly opposed its continuation for the 2025 season.

The Saints' win over Fremantle was one of their most complete performances of the year, making the need to activate a sub unnecessary from a strategic standpoint.

This is now the second week in a row Lyon's handling of the sub has raised eyebrows, after second-year midfielder Hugo Garcia was subbed out at half-time in their previous match against Brisbane.

Garcia responded in the best possible way, earning a Rising Star nomination for his standout performance against Fremantle, which included 19 disposals, 10 tackles and a goal.

With Travaglia's situation reigniting debate around the sub's value, Lyon's comments may again put pressure on the league to review the rule and its future in the competition.