First-round draft pick Ben McEvoy has been told he will make his debut against Fremantle on Friday night, while fellow youngsters Jarryd Allen, Robert Eddy and Brad Howard are also in the selection mix.
"Reputations count for nothing when you’re 5-7 and you’ve won one out of your past five," he said.
"We’ll reward and encourage those that do what we want and those that don’t will have to go back and develop the habits that we’re looking for and create an opportunity for themselves again."
Lyon said he was excited to pick McEvoy, who will share the ruck duties with Steven King in place of injured ruckman Michael Gardiner.
"He’s a very level kid, he’s very mature for his age and he knows what the business is about. He is expected to perform a role for the team in the ruck and up forward," he said.
"He should cope and it will be a good challenge. [Steven] King is very experienced and a strong leader. He’ll be able to guide him through."
Matthew Ferguson is a chance to return after he was withdrawn in the lead-up to last week’s loss to the Sydney Swans, while veteran Robert Harvey is expected to recover from a calf twinge he sustained early in the match.
But Justin Koschitzke will miss another week as he recovers from a jarred knee, sustained in the round 11 game against the Western Bulldogs.
Lyon admitted he was taking a conservative approach to the big man's injury.
"We’re hopeful he’ll be available next week. He’s not doing full training," he said.
"It (the knee) did hyperextend a bit. The scan revealed he got out of jail because he could have torn an ACL or a PCL."
Lyon refused to concede that a loss to 14th-placed Fremantle would signal the end of St Kilda’s season but indicated he wasn't just focusing on making the finals.
"Finals are the results," he said. "There are some teams in the competition that can plan for finals but we’re really about winning games and developing the team. We want to take care of the mechanics of the game and dynamics of the team and the results will follow.
"We’ve won one of our last five but we’re only a game out of the eight. You can’t rely on teams losing and we need to win."
