On a weekend that saw the Saints lose their 10th straight match, they also suffered a string of injuries that will further hurt their depth in the final seven rounds.
Forward Tom Lee will undergo surgery for a shoulder injury on Friday with a return date to be confirmed, while Beau Maister has been ruled out for the rest of the season with a dislocated AC joint.
Meanwhile, Nathan Wright suffered his second concussion this season in the VFL and will miss one match with the Saints taking a cautious approach with the midfielder.
Arryn Siposs aggravated a shoulder injury and will miss up to two weeks, suffering the same injury twice in a fortnight.
The injury to Steven, who missed the first three matches this season with a foot injury, will hurt more than any other, with the speedy midfielder one of St Kilda's most important players.
He could return for the round 20 clash against the Western Bulldogs.
"Jack has experienced some leg soreness in recent weeks which our medical team feels is best treated through rest and rehabilitation, " head of football Chris Pelchen said.
"While the injury provides him with some frustration to an already interrupted season, we are confident that he will return to the AFL team before the end of 2014."
