Triple sweetness! Now I understand. I think I'll use the following version, because it gives me the same end result (having a double-quoted replacement expression on the final evaluation) and allows me to use the replacement expression as it is given to me.

#!/usr/bin/perl -w
use strict;

my $find = 'proof(\S+)';
my $rpl  = 'read$1';
my $text = 'proofing is proof it needed to be proofed';

if ($text =~ s/$find/"\"$rpl\""/ee) {
    print "1st replacement made:\n\t$text\n";
}
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