Castro hasn't played in Glory's past two games due to a hamstring injury and was listed as three weeks away from playing when Perth announced their squad on Thursday.

But the 34-year-old has seemingly completed a remarkable recovery, with Lowe telling reporters on Friday that Castro could be involved against Hyundai A-League leaders Sydney on Saturday night.

"I think he'll be on the bench, which is a big boost for everyone," Lowe said.

Castro has scored two goals and notched one assist in eight games this season.

The Spanish attacker was named the A-League's best player in 2015/16 after scoring 13 goals and setting up another two for Glory.

Castro's return couldn't come at a better time, with Perth hoping to bounce back from a shock 2-1 home loss to Newcastle Jets last week.

Glory have registered only one win in their past seven matches and Lowe declared "we let everybody down" with their first A-League defeat at nib Stadium since January.

"History says that that's not the norm, so I'm expecting a reaction from the players," Perth's coach said.

"The players are expecting a reaction from themselves and a positive reaction, so hopefully we see that at the weekend."

But although Glory are clearly hurting this week, Lowe attempted to cast their current slump in a positive light.

Perth sit fifth in the A-League table ahead of their Round 11 fixture against the Sky Blues.

"The big thing is we're sitting in a final's position with a possibility of moving upwards and, like I said, at the moment that's not acceptable, which is amazing for us as a club because it shows how far we've come," Lowe said.

"Now we what we need is to grasp the situation and kick-on up the league."