Space in Source URL – Redirection Plugin Not Working

I’m trying to figure this out, as well.

I have space between the first name and last name in url, like this: http://mysite.com/contributor/john doe

It needs to be like this: http://mysite.com/contributor/john-doe

Here is what I “thought” should work:

Source: /contributor/(.*)\s(.*)
Target: /contributor/$1-$2

I get a redirect loop. Any ideas?