Defensive Line: Josiah Bronson
Up front on defense, the Dolphins' interior line is pretty set. Last year, Miami rolled with Christian Wilkins, Raekwon Davis and Zach Sieler as the only three and it worked. But, they could afford to use one more spot on this area if they are able to.
if the Dolphins keep one more guy up front, it very well may be one of veteran Josiah Bronson or rookie undrafted free agent Brandon Pili out of USC. Between those two, I would bet the rookie makes a push for a spot. Bronson hasn't done much in a couple of years as a pro.
Linebacker/Edge: Duke Riley
The Dolphins' linebackers and edge group is a strength. Their starting four include Bradley Chubb and Jaelen Phillips outside, with David Long and Jerome Baker on the inside. There are a few different players who could compete for a spot, here, but two of the first reserves to make it should end up being Andrew Van Ginkel and Emmanuel Ogbah on the edge.
Beyond those guys, it's tough to project. One of the last key reserves could end up being linebacker Duke Riley, and/or Channing Tindall. It really depends on how many linebackers Miami wants to keep, here. Riley has spent the last two years with Miami as a reserve, so he might have the best chance to stick over all the rest.