Sydney will be nervously awaiting the 2022 AFL finals schedule after gun forward Tom Papley suffered a concussion in his side's clash with St Kilda.

The head knock was a result of some friendly fire with teammate Lance Franklin, prompting the Swans to use their medical sub in the opening half.

Sydney confirmed Papley had suffered a concussion in the knock, meaning the All-Australian forward will be required to follow the AFL's 12-day concussion protocol period.

The sideline stint will place Papley out of action and training until Friday, September 2 - what will likely be the second day of the opening week of finals.

The AFL are expected to schedule a Thursday night fixture among the four matches to start the post-season, with Papley to miss the match should Sydney be scheduled to open finals.

A large enough win over the Saints will see the Swans clinch a top-two finish and home qualifying final, while a third-placed finish looms just as likely should they win by a smaller margin.

A loss will hand third place to Collingwood, with Sydney taking fifth place and Fremantle holding a spot in the top four.

The AFL are expected to release the week one finals fixture shortly after the end of Round 23.