The Dockers had 21 of the 22 from last year's Grand Final fly to Melbourne on Wednesday, with Nick Suban the only player missing due to his one-week suspension.
Sylvia, Clancee Pearce, Tommy Sheridan and Jack Hannath were the four additions from last year's Grand Final team.
Zac Clarke has travelled but Lyon all but ruled out the ruckman due to his knee concern, saying Hannath was a certain starter.
But Lyon was far less forthcoming when asked whether Sylvia would make his debut for his new club.
"Well, he might be in yet," Lyon said.
"Not many surprises left in life so we’ll leave one.
"He’s in the 25. We’ve got some flexibility to fine-tune things, see how everyone pulls up without being too cute about it, then we’ll name our final 22.
"He’s played two-and-a-half practice games, so he’s got about 260 minutes of AFL football. He’s finally got some continuity but there’s some people in form as well that he has to try and go past.
"Danyle Pearce had been under a little bit of doubt but he trained fully. With those guys you’ve got to see that they train and it’s really 24 hours after the flight, how they pull up."
Sylvia has had an indifferent maiden pre-season at Fremantle - he played in the first intra-club match and in the NAB Challenge loss to West Coast, where he collected just five possessions.
The former Demon then missed the NAB Challenge win over the Western Bulldogs due to concussion from a head knock at training and did not play against the Eagles in last Thursday's practice match. However, he did play in a WAFL pre-season match for Peel Thunder on Saturday.
Lyon confirmed that reigning best and fairest Nat Fyfe and livewire forward Hayden Ballantyne would play despite both missing last week's practice match due to injury.
Fyfe wrenched his knee against the Bulldogs a fortnight ago but has overcome that issue to train fully this week while Ballantyne suffered a corked thigh in the same game that took longer than expected to overcome.
Lyon travelled to Metricon Stadium on March 2 to watch Collingwood's 14-point practice win against Gold Coast live and was impressed by the Magpies' midfield strength.
"They've got good resilience and fitness base," Lyon said.
"The clearance work was very good. Their midfield really got to work – Dane Swan, Scott Pendlebury, Dayne Beams, Luke Ball, Clinton Young, Steele Sidebottom and young Brodie Grundy and Taylor Adams. We know their mix in the midfield is as good as anyone's.
"Once they got on top, they gave Travis Cloke really good supply, and he was able to do some damage.
"They kicked a lot of goals from clearances.
"We've got a handle of them. We've still got some more work to do to prepare."
