With the WEC/UFC merger that everyone was so giddy about coming to pass, there were some consequences as well. The UFC, who for the most part already has trouble getting its current roster 3 fights a year, would struggle to properly book its current bloated roster. As you've seen, the UFC has been in Edward Scissorhands mode, cutting fights left and right to alleviate the size. Well from Dave Meltzer's latest Wrestling Observer, he states the following:
Another thing that is likely to happen is that some UFC prelim fighters will be given the opportunity to take fights outside the organization and remain under contract simply so they can get three fights in. Also, if you aren't a big name, the leverage in turning down fights is a lot smaller because the roster spots are so competitive. They've added a 12th fight on a lot of the shows so they can keep talent busy but even with an addition of one fight per show this year, so that helps some as it's the equivalent of adding 16 usable roster spots.
Allowing fighters to fight outside the UFC is a big step especially when you consider how small the number of fighters are who actually get 3 fights in a year. And now with two more weight classes coming in and only a couple added shows, that number will definitely get larger.