Keogh, 28, was charged with disorderly behaviour while 22-year-old Risdon was charged with failing to follow a police direction to leave the area in question.
Both players were fined by the club and issued apologies to their team-mates and the Glory supporters.
With the charges having been dropped, the pair will no longer be required to attend an Adelaide magistrates court this month.
"After taking into account the circumstances including the fines issued against the men, the decision has been made not to proceed with any other charges," SA Police said in a statement.
"Their bail has been cancelled and they are not required to appear in court."
Perth are fourth on the A-League table, two points behind leaders Wellington Phoenix. They play the Central Coast Mariners away from home on Sunday.
