Drilling in: Dolphins unit by unit analysis

QUARTERBACKS: Starter -- Ryan Tannehill. Backups -- David Fales, Brock Osweiler, Bryce Petty. Tannehill is a reliable starter, we all know that. But he must play at a near-Pro Bowl level for this offense to really hum. He was on such a path in 2016, when he missed the last three games due to a knee injury. The challenge now is to improve on that performance. If Tannehill goes down again, it's bleak. Neither Osweiler, Fales nor Petty instills much confidence. RUNNING BACKS: Starter -- Kenyan Drake. Backups -- Frank Gore, Senorise Perry, Kalen Ballage, Brandon Radcliff, Buddy Howell. Drake is the key. It's unclear if he can be a 1,000-yard rusher, but if he can amass 1,000 yard from scrimmage that would be acceptable. Gore provides a solid No. 2 punch. Remember, head coach Adam Gase has said he wants a two-back system. If Drake and Gore move the chains on the ground and in the air, look out. If they struggle it likely puts too much pressure on Tannehill and the passing game. TIGHT ENDS: Starter -- Mike Gesicki. Backups -- Durham Smythe, MarQueis Gray, A.J. Derby, Gavin Escobar, Thomas Duarte. The starting job should belong to Gesicki, the second-round pick from Penn State. He's long and athletic and seems to fit the Gase offense perfectly. Smythe, the fourth-round pick from Notre Dame, also seems a perfect fit as an in-line blocker and occasional receiver. At that point it's likely between Gray and Derby for the final spot. But training camp could provide a surprise at this position. WIDE RECEIVERS: Starters -- Kenny Stills, DeVante Parker, Danny Amendola. Backups -- Albert Wilson, Jakeem Grant, Leonte Carroo, Malcolm Lewis, Rashawn Scott, Isaiah Ford, Francis Owusu, Drew Morgan. This could be the best unit on the team, and the top four -- Stills, Parker, Amendola and Wilson -- are the ones who make this thing go. Ideally, they are able to be threats at all three levels, plus on third downs and in the red zone. Their biggest asset is their collective threat as opposed to individual skill. That's the ideal. In reality, Parker could again underachieve, the 32-year-old Amendola could be losing a step, and Wilson could be only so-so. It's all about those top four receivers. OFFENSIVE LINEMEN: Starters -- LT Laremy Tunsil, LG Josh Sitton, C Daniel Kilgore, RG Jesse Davis, RT Ja'Wuan James. Backups -- T Sam Young, RT Eric Smith, LT Zach Sterup, G Ted Larsen, G Isaac Asiata, C Jake Brendel, C Mike Matthews, T Joseph Roubbens, T Eric Steinmetz, C Connor Hilland. The keys are the tackles, Tunsil and James. If they can't protect Tannehill, it's going to be nearly impossible to throw intermediate and deep passes. And there's legitimate question as to whether they can be effective. The middle of the line has two newcomers in Kilgore and Sitton and a relatively new starter in Davis. Depth is OK, so for the first time in years this isn't one of the team's top concerns. Just keep an eye on Tunsil and James. DEFENSIVE LINEMEN: Starters -- LDE Cameron Wake, LDT Jordan Phillips, RDT Akeem Spence, RDE Robert Quinn. Backups -- DE Charles Harris, DE William Hayes, DE Andre Branch, DT Davon Godchaux, DT Vincent Taylor, DT Gabe Wright, DE Cameron Malveaux, DE Johnathan Woodard, DE Quincy Redmon, DE Claudy Mathieu, DT Anthony Moten, DT Jamiyus Pittman. Defensive end, led by Wake, Quinn and Branch, could be the best position on the team. They seem to have it all as far as depth, experience and big-play ability. If Harris, the 2017 first-round pick, comes around, this is a dangerous crew. Defensive tackle is at the other end of the spectrum in that it's eyed suspiciously. Phillips has been inconsistent and Spence isn't an ideal fulltime starter. This crew should be strong on the outside, but there are major questions inside. LINEBACKERS: Starters -- OLB Kiko Alonso, MLB Raekwon McMillan, OLB Stephone Anthony. Backups -- MLB Chase Allen, OLB Jerome Baker, OLB Terence Garvin, OLB Quentin Poling, MLB Mike Hull, OLB Mike McCray, OLB Cayson Collins. This is the biggest question area on the team. There's a lot riding on the shoulders of McMillan, the 2017 second-round pick who missed the season with a knee injury. DT Ndamukong Suh is no longer there to tie up offensive linemen, so his job becomes tougher. Alonso was lacking in pass coverage last year so replacing him with, say, Baker, would be ideal. Depth is average. This position lacks starting-caliber power. If they get that corrected the defense will be OK. If not, the defense is in for a long season. DEFENSIVE BACKS: Starters -- LCB Xavien Howard, RCB Cordrea Tankersley, S Reshad Jones, S T.J. McDonald. Backups -- Nickel CB Bobby McCain, S Minkah Fitzpatrick, CB Tony Lippett, CB Jalen Davis, CB Walt Aikens, CB Torry McTyer, CB Taveze Calhoun, CB Cornell Armstrong, CB Johnathan Alston, CB Jordan Lucas, S Maurice Smith, S Trae Elston. This could be a team strength if the boundary corners come through. McCain is solid in the slot and Miami is set at safety between Jones and McDonald. Adding Fitzpatrick can only help at that position. At boundary cornerback, Howard is fairly reliable but lacks polish. Tankersley was so-so last year. Lippett, who missed last season with an Achilles injury, could fight for a starting job. If Miami finds two solid corners this should be a playmaking secondary. At worst, they should be average. SPECIAL TEAMS: K Jason Sanders, K Greg Joseph, P Matt Haack, LS John Denney, LS Lucas Gravelle, KOR/PR Jakeem Grant, PR Danny Amendola, KOR Kenyan Drake. Miami is searching for a kicker between a pair of rookies -- Sanders, the seventh-round pick, and Joseph, who was undrafted. Haack should show improvement after an up and down rookie season. Grant is solid in the return game. Don't expect Amendola or Drake to see much time there early in training camp. It's unclear whether this unit will have game-changing potential. But if they can settle the kicker position with a reliable performer, that would be good enough.