Would the {exp:playa:parents}
tag do the trick?
Essentially your looking for all of the entries (parents) which have a team member set to be the author. You could loop over your team members (or potentially one member, if it's the member permalink page) and then use the {exp:playa:parents}
tag to pull your specific articles. The parents tag also supports all standard channel:entries tags, so you could do further refining with the search parameter if necessary.
http://docs.pixelandtonic.com/playa/templating/module/parents.html
Update: Updating my answer after clarification
What about adding something like this, which would be cached to help performance?
{exp:stash:set_list name="members"}
{exp:channel:entries
channel="blogs"
search:member="not IS_EMPTY"}
{stash:name}{member_name}{/stash:name}
{/exp:channel:entries}
{/exp:stash:set_list}
{exp:stash:get_list name="members" unique="yes"}
{name}
{/exp:stash:get_list}
So in the above code, we're pulling back all blogs that have the member field not empty. You'll notice this loop has a {stash:set_list} surrounding it which lets us store each item in a list.
After that chunk of code we use the {stash:get_list} to pull back our list of names, and we specify the unique parameter so we don't return multiple names that are the same.
I didn't test the above code, so definitely check the syntax, but hopefully that would work. Also, check the stash docs for more info on those tags, https://github.com/croxton/Stash/wiki