The 31-year old Australia international limped out of training with a thigh problem, adding to the Glory's growing injury list.
With skipper Jacob Burns, Socceroos striker Mile Sterjovski, first-choice goalkeeper Tando Velaphi and key midfielders Adriano Pellegrino and Victor Sikora already experiencing injury troubles, Coyne's setback may make life tough for Dave Mitchell's team who are chasing fourth position for a home final.
"There is no call to be made yet, and we want to make sure they get through training and see how they feel. But Mile is more likely than Jacob," Mitchell said.
"It was a cork (for Coyne), he is getting treatment immediately and hopefully he will be OK. If it is the best thing to do he will have to miss out.
"It would be a blow, but hopefully it won't be. You don't want to risk players, to make sure they are available for the week after."
The Glory need Central Coast Mariners to either defeat or hold Wellington Phoenix (who hold fourth spot) to a draw on Friday night, then gain three points by beating the Roar at home but Mitchell is aware it is not quite as simple as just saying that.
"Going into the game we will know what Central Coast will have done, which will be a bit of bonus for us," Mitchell added.
"We are strong at home, so hopefully the Mariners get a result over there. It is a big ask, but it Lawrie's last game and he will probably want to go out on a strong note.
"The A-League is that topsy-turvy you never know what is going to happen - we have just got to make sure we hold up our end of the bargain which is win the game."