On the day that the Lions are expected to release at least four players, they have also cut their alternate black uniforms. The black uniforms were created in 2005 and introduced by Matt Millen, who I'm guessing also had a pretty big say in adding a black outline to the logo. Having black uniforms as the Lions' third uniform meant that the throwbacks traditionally worn on Thanksgiving were gone. The black jerseys were worn on Thanksgiving instead (for a couple years anyways) and on other occasions as well.
In 2008, the Lions were able to wear their throwbacks on a couple occasions as part of festivities for their 75th anniversary. After it was announced that the throwbacks were returning, the feeling was that their return would be permanent, especially after Millen was fired. As we now know, their return is indeed permanent, as the throwbacks are now the Lions' alternate uniform once again.
Tom Lewand also mentioned to Tom Kowalski that "minor" logo and regular jersey changes are possible, though nothing would likely happen this year. This is just pure speculation on my part, but if minor changes were to happen, it would probably be the removal of the black outline on the logo and anything black on the uniforms. I guess we'll have to wait and see to be completely sure, but I just don't see minor changes altering anything more than something like an outline color.