St Kilda forward Josh Bruce has suffered a fractured fibula at training on Thursday, likely ruling him out for the rest of the season.

Defender Jake Carlise has suffered a minor puncture to his lung and will not play against Port Adelaide this Saturday at Adelaide Oval.

Saints general manager of football Simon Lethlean was hopeful Carlisle would only miss one week.

“There is a small risk in treating rib injuries that this type of complication can occur,” Lethlean told saints.com.au.

“We’d love to have them both out there this weekend but the reality is they won’t be, and we will need guys to step up and fill the void.

“We have seen a host of young players take their opportunity over the course of the season, and we need this to continue this week.”

It is a cruel blow for the Saint who are struggling in 15th place this season, but were finally gaining some momentum following last week's shock two-point win over Melbourne.