I think this is a very interesting development. Jermaine Phillips moved from strong safety to weak side linebacker. He's definitely physical and he's worked well in the box in the past. I know the team will use the Tampa 2 to a lesser degree now and is looking to be more physical as well as bigger so it makes sense that Phillips would replace Derrick Brooks, a weak side linebacker that is smaller than Phillips by about two inches.
The Bucs are a bit of a mess at the moment, they also have a guard who is having concussion problems.