That means 18-year-old Matt Davies, Riley Woodcock, also 18, and 21-year-old Jack Clisby are all likely to get gigs in defence this week.
Glory will also be without suspended skipper Jacob Burns, while Smeltz has been ruled out for up to a month after damaging ankle ligaments during last week's 1-0 loss to Brisbane.
Smeltz missed the start of the season after undergoing surgery on his hip, and his latest injury setback comes at a bad time for Perth, who are already without a host of their best players.
Pantelidis, who won an A-League title with Melbourne Victory in 2006/07, had been a vital cog at the Glory since linking up with the club in 2011.
The 30-year-old had played predominantly in defence, but the arrival of former French international Gallas meant Pantelidis would have been squeezed out of a starting berth.
"Steve has been a great servant to Perth Glory over the past two years,'' Glory coach Alistair Edwards said. "We were in talks to extend his contract further.
"However, we had also received significant interest from a number of clubs in Asia for him.
"There is increasing money going into football in Asia and the Malaysian league is fast attracting a number of overseas players.
"As a club, we do not want to stand in the way of (a) player seeking to pursue overseas aspirations.''
Consecutive losses have resulted in Perth slipping to seventh on the table.
-AAP
