Dolphins need a new middle linebacker to fix a long-struggling unit

T.Y. Hilton of the Colts is chased by Kelvin Sheppard of the Dolphins (Getty Images)In 2012, the Dolphins had a solid middle linebacker in Karlos Dansby.

But they decided to blow up the group, which also included Kevin Burnett, to make room for Dannell Ellerbe and Philip Wheeler.

It’s been all downhill since.

Ellerbe, who played mostly outside linebacker with Baltimore, was mediocre inside and then suffered a season-ending injury to start his second year with Miami.

Wheeler — who was best in Indianapolis and Oakland as a pass rusher — was miscast with the Dolphins, who would try to use him in coverage.

They moved on from both in 2015, but the struggles continued.

In 2015, Miami initially…