There is no one currently on the roster that can come close to replacing Ogunleye. David Bowens won't match his sack production and will never be able to hold up against the run as a 3 down defensive end. Jay Williams will never consistently give the type of pass rush we need from that spot.
Otis Grigsby has a motor, but this is a guy who had 10 sacks in his college career. He's not a pass rushing threat. A good special teamer, but not a pass rusher.
By getting rid of Ogunleye, the Dolphins would simply be creating a gaping hole on their defense. Great pass rushers like this are hard to find. Miami should have locked Ogunleye up to a long term deal LAST YEAR!