How about this for a different way to do it.

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

my $string = q{"2","T,E,S,T,B","Lazowsky","Mike's","Teststring"};

$string =~ s/,(?!")//g;

print qq{[$string]\n};
[download]

Outputs: ["2","TESTB","Lazowsky","Mike's","Teststring"]

Uses Negative Lookahead Assertion.
Essentially, this is saying, to remove any commas, as long as they are not followed by a double quote.

Warning: definitely not production code, there are several problems with this.
Text::CSV, is the way to go.

Best Regards,
Wonko