Although the Suns (3-17) are playing for little more than pride against Melbourne and Hawthorn in the final two rounds, McKenna said the coaching staff would be monitoring performances closely.
Gold Coast has 14 players coming out of contract and need to cut between six and eight players to reach next season's list limit of 46.
McKenna said the match committee was far from settled on which players would get the chop, but every contest, every quarter and every half would help the decision.
"From a club point of view, there's nothing much to gain, but individually and collectively there's a lot for some players," McKenna said.
"If they choose to drop off, we'll soon understand that when things get tough, he's probably a player we don't need on our list and that's what we'll find out over the next two weeks.
"There's two opportunities to tick the box, cross the box or still have a question mark there. Then we'll sit down with [list manager] Scott [Clayton] and the match committee and work out who is here. If you get your opportunity it's all about taking it."
McKenna said improvement over the entire season would largely determine contracts, but his message was clear not to switch off.
One player likely to show his wares at the MCG on Sunday is Josh Caddy, the No.7 pick from the 2010 National Draft.
Caddy has been sidelined since suffering a stress fracture in his navicular (foot) in the NAB Cup, and after three games - where he played a quarter, a half and three quarters - in the reserves, is ready to make his senior debut.
"He's a very big chance, a very big chance," McKenna said when asked of his possible inclusion.
One man that will miss is ruckman Josh Fraser, who lost 5kg while playing Adelaide last Saturday due to illness and has not recovered.
He will be replaced by Zac Smith who was rested last week.
McKenna said the Suns had to make the most of their first opportunity to play at the MCG this season.
"I think every game has been a huge challenge for [the young players]," he said.
"We want to know that our season ends in two weeks, not after five or 10 minutes of a spirited effort against Melbourne at the MCG. We want to make sure our finish line is round 24. We want to hit that tape with some confidence."
Michael Whiting covers Gold Coast news for afl.com.au. Follow him on Twitter: @mike_whiting
