THE SYDNEY Swans and Fremantle will go into Saturday night's preliminary final as named, with the Swans not gambling on the fitness of premiership player Lewis Roberts-Thomson.

The Swans swingman travelled to Perth as an emergency and was considered a chance to return from injury for the cut-throat final.

However, the Swans haven't taken that risk.

Roberts-Thomson played a key role in 2005 when the Swans broke their long premiership drought, but has been hampered by a knee injury this season.

He last played AFL in round four and only returned to play 80 minutes in last weekend's reserves game.

The Swans have named speedster Gary Rohan as their substitute.

The Dockers are also unchanged, with Lachie Neale their sub.