A report by Back Page Football revealed Keogh is expected to sign a two-year deal with Saudi club Al-Qadsiah after turning down the approaches from A-League clubs Newcastle Jets and Adelaide United.
The former Republic of Ireland international was Glory's leading goal scorer last season but is not in Popovic's plan's for the upcoming campaign.
The 33-year-old signed a one-year contract extension in March but was forced to train on his own after returning from his off-season break as the Glory delayed his mandatory medical.
After weeks of training alone he was finally informed this week he would have to look else where for first team football.
“I wanted to see out my playing days at Perth Glory but unfortunately things haven’t worked out this offseason and I have been given a great opportunity in Saudi Arabia," he told Back Page Football.
“I don’t want to play for another club in the A-League or have to sit out a season due to being out of favour."
Keogh signed with Perth in 2014 and has gone to score 55 goals in 122 appearances for the club which is a club record.
He was not included in the Perth squad for their pre-season clash against Manchester United with new signing Bruno Fornaroli instead leading the line.