Baker hasn't played since he was suspended for nine weeks after a round 13 clash with Geelong forward Steve Johnson.
A foot injury sustained during his stint on the sidelines hampered his chances of an immediate recall and he has been named an emergency in each of the Saints' two finals.
Lyon was coy on Baker's chances of returning to face the Magpies on Saturday but he said the hard-nosed midfielder was in the mix.
“It’s pretty hard to give you a percentage, isn’t it?” he said.
“He’s in the 25, but we had probably six players come here and get ready ... if something had have happened to the others, which can happen, so we’ve got about 31 to pick from.
“Obviously he’s very respected and he’ll give himself his best chance. It will be horses for courses. The Bulldogs’ front six is certainly different to Collingwood’s front six.”
Speaking after the Saints' 24-point win over the Western Bulldogs in Saturday night's preliminary final, Lyon paid tribute to his players' ability to achieve under adversity.
“We’ve faced significant challenges that are well-documented and at no stage have we been distracted or given up. I think we’ve been mentally and physically tough.
“That’s the aim; to produce that [again] next week. It’s a coveted prize and everyone is going to be up for the challenge so it’s going to be difficult.”
The Saints’ shot at redemption looked anything but certain during the first half of a preliminary final in which the plucky Dogs took it right up to their better-fancied opponents.
Trailing by a goal at half time, St Kilda piled on seven goals to one in the third term on the back of a magnificent display from skipper Nick Riewoldt.
However, Lyon was reluctant to praise Riewoldt's effort at the expense of his teammates' contributions.
“I think we’ve got to be a little bit careful. I think he played well but the midfield really got to work in there," he said.
"I thought the other forwards worked off him and provided pressure to allow Nick to stay in the contest whereas in the first half, there was that one back.
“I think we acknowledge that he led the team really well but it’s about 22 players in these games really contributing. I thought that’s what the Bulldogs did but in the end we imposed our will on the game.”
Nick Dal Santo (hamstring) and Jason Gram (groin/quad) both looked uncomfortable in the second half, but Lyon declared them certain starters for the premiership decider with their issues nothing more than cramp.
Lyon said the experience of the 2009 grand final loss to Geelong had left his side better prepared for Saturday's decider against Collingwood, but he said it was ultimately just "another game of football."
“We know ... that finals are a random-chance small sample so we know anything can happen. No one understands that better than this football club," he said.
“We create another opportunity and try and take hold of the opportunity.”
