The former Huddersfield goalkeeper has been in superb form for Rangers this season, making a string of fine saves.
Perch came back into the team at Preston, where goalkeeper Smithies made a clutch of stunning late saves to keep the score down to 2-1.
The versatile defender reckons the stopper, who signed a new deal with the club earlier in February, would command a hefty fee.
“I don’t want to put a price on him! That’s up to the club,” Perch commented. “He’s worth a lot, that’s all I can say.
“It could have been a lot more than that at Preston had he not made those saves.
“He’s been like it all season. I don’t want to label him but for us at the minute he’s impenetrable.
“Luckily, we’ve tied him down to a new deal.”