If you completely trust your $outputString not to have anything malicious in it, you could use string eval.

$searchString = '(T)(est).(\d{2}).*';
$outputString = 'This $3 a $1$2';
$sampleData = "Test 22";

$sampleData =~ /$searchString/ && eval qq{print "$outputString"};
print "\n";
__END__
This 22 a Test
[download]

I think, however, this should be considered a last resort.