WEDNESDAY'S training session will determine whether key St Kilda midfielder David Armitage will play against Collingwood on Friday night after overcoming a nasty knee laceration.

Armitage hasn't played since the Saints' round four loss to Adelaide, where he sliced open his left knee on the sole of Patrick Dangerfield's boot.

He had the cut – which exposed his kneecap – stitched and played out the game but developed an infection from soil that got into the wound.

Armitage was in hospital for a week and a half and underwent two procedures to remove the infection.

While he's on the cusp of a return, coach Alan Richardson said Armitage was a "chance" this week but the club had to consider the risk of him not being ready for a full game.  

"He (Armitage) is a chance. We've got a really significant session now given we don't play until Friday,” Richardson said on Wednesday before the session in Seaford.

"We'll see how Dave goes. It would be fair to say he's probably less likely than likely but he's incredibly keen to play. He's one of the leaders and he realises we've got a pretty young group and he's very important to our future and direction.

"He wants to get out there and help but we've got to make sure we do the right thing by him and the team."

Seb Ross is rated a "significant chance" to face the Pies after a strong few weeks in the VFL, given Blake Acres' ankle injury will force at least one change.

Awaiting the Saints on Friday night is a strong Collingwood midfield but Richardson is comfortable with the outfit he will select to play them.

"Friday night footy – we haven't had this opportunity (this year) so it's really exciting for the players," Richardson said.

"They (Collingwood) are a good team in good form, they've got some quality out there.

"We've got some young players and we've got some experienced leaders that have been really strong for us so it's really exciting.

"We've got a pretty good group that will represent the club in the midfield.

"Whoever plays on those players will play strong, two-way footy." 

While Richardson said it was disappointing to go into the bye after a loss, particularly after the Saints showed fight in the second half against Gold Coast two weeks ago, he admitted the break came at an ideal time.

"We were probably a little bit banged up - our younger players have had to play some really significant roles and minutes," he said.

"While long term that's outstanding for our club and those guys, it was good timing for them to have a break."