Five key questions for the Miami Dolphins on defense as camp nears. And potential answers

With training camp set to open next Wednesday, examining five key questions facing the Miami Dolphins in training camp and preseason on defense:

▪ How much does edge player Melvin Ingram play, if he sticks?

That will depend on training camp and preseason performance and production. He could spell Emmanuel Ogbah (who played 67 percent of the defensive snaps last season) or Andrew Van Ginkel (71 percent) or take time away from Brennan Scarlett, who played 19 percent of the Dolphins’ defensive snaps last season.

Scarlett, incidentally, said he is being used more at defensive end after playing linebacker last season. I doubt Ingram takes many snaps away from Jaelan Phillips.

Though Ingram isn’t a tackle, as an FYI, Christian Wilkins played 65 percent and Adam Butler played 53 percent of Miami’s defensive snaps last season. There are alignments where Ingram perhaps could take some time from Butler, though Butler isn’t an edge player.

Last season, Ingram played 58 percent of the Chiefs’ defensive snaps in his nine games for Kansas City and 62 percent in his six games for Pittsburgh.

I wouldn’t expect him to play as much as that here, barring injuries or something unforeseen.

None of Ingram’s $1.7 million salary is guaranteed, so he can’t be a disaster in August. His $3.9 million cap hit shrinks to $1.6 million if he’s cut.

▪ Who’s the No. 3 inside linebacker behind Jerome Baker and Elandon Roberts?

Duke Riley played 21 percent of the Dolphins’ defensive snaps last season (227 in all) and the question is how many of those snaps will be poached by Channing Tindall, the rookie third-rounder.

At least initially, I would expect Riley to play more; Riley was very good in OTAs, while Tindall was hit and miss, as you would expect from a rookie.

Tindall is probably the better pass rusher; Riley has 0.5 career sacks, partly a result of a lack of usage as a rusher.

Conversely, as a pass rusher, Pro Football Focus rated Tindall 28th of 333 linebackers who had enough pass rush chances to qualify. He had 5.5 sacks last season and 12 in his career at Georgia.

Who will ultimately be better as a run defender at the NFL level is unclear; Riley gets the nod at this point in their careers. If Riley had enough snaps to qualify, he would have tied for 30th as a run-defender among 87 linebackers who qualified for PFF’s metrics.

In the area of defending the run, PFF rated Tindall 218th among 830 FBS linebackers last season.

Riley graded out well in pass coverage; quarterbacks had just a 67.9 passer rating in his coverage area last season, with six catches in 11 targets for 53 yards.

Tindall’s pass coverage numbers at Georgia last season were OK: He was targeted 17 times and allowed 13 receptions but for only 72 yards.

If the Dolphins use Tindall as a blitzer - which is a strength - that might mean using Jerome Baker more in coverage. Baker already is one of the league’s best blitzing inside linebackers.

Here were passer ratings against, for the other Dolphins linebackers: Roberts 85.8 (24 for 33 for 283 yards, a TD and a pick returned for a TD), Phillips (88.5, but just four completions), Baker 91.1 (46 for 64, 387 yards, 2 TDs, 1 INT) and Van Ginkel 115.5 (22 for 26, 225 yards, 1 TD).

This ultimately comes down to whether the staff trusts Tindall more than Riley early in his rookie season; I doubt that they would.

Another factor is whether defensive coordinator Josh Boyer decides to create a package for Tindall to blitz a few times a game, which would seem sensible considering Tindall’s skills as a pass rusher.

For now, Riley enters camp as the clear front-runner to be the top backup behind Baker and Roberts, who plays on traditional running downs.

▪ Who’s the No. 4 cornerback in the dime packages (or if there’s an injury)?

The Dolphins used a natural fourth cornerback not very often last season, and their primary fourth corner - Justin Coleman - wasn’t resigned and is now with Seattle. Their preferred six-defensive back package features three corners (Xavien Howard, Byron Jones and Nik Needham) with three safeties (Jevon Holland, Brandon Jones, Eric Rowe).

So the Dolphins likely will need a fourth cornerback only if someone is injured or Needham regresses. And that comes down to a battle between Noah Igbonoghene, Trill Williams, Quincy Wilson (the former second-rounder with 12 starts for the Colts and Giants) and - less likely - D’Angelo Ross or undrafted rookie Kader Kohou. The Dolphins are looking at Wilson at safety.

If Igbinoghene is pretty good in camp and preseason games, the No. 4 job is likely his. But Williams and Wilson shouldn’t be discounted. At some point, the Dolphins need a return on the Igbinoghene first-round investment; new defensive backs coach Sam Madison said he “is in a very good place. He has some talent, has some speed.”

Byron Jones, incidentally, will begin camp on PUP (physically unable to perform). He had surgery in March in an area around his ankle and Achilles. A source said the timetable for recovery was three months. So barring a setback, the thought has been that he would be ready for the season. He can be activated off PUP at any time.

▪ Will Phillips show enough to be an everydown player?

Among 113 qualifying edge players, Pro Football Focus rated Van Ginkel 75th and Phillips 93rd. Though Phillips had 8.5 sacks as a rookie, PFF rated him just 102nd as a run defender.

And that must improve for the Dolphins to consistently trust him as a first and second down player. He has dropped a few pounds but said he expects to be stout against the run and would love to play most every down.

Phillips played 54 percent of the Dolphins’ defensive snaps, compared with 92 percent for Baker and 71 percent for Van Ginkel. If Phillips continues to improve, that number should go up.

▪ What undrafted rookie could stick and what veterans are at risk?

Among seven undrafted rookies, a longtime scout said he doubted any of the 53 will make the roster but didn’t rule out Oregon safety Verone McKinley III and Texas A&M Commerce cornerback Kader Kohou as long shots. The numbers are working against both. Neither stood out in OTA sessions open to reporters.

Among veterans, linebackers Sam Eguavoen, Scarlett and Calvin Munson all stand at varying degrees of risk, but Scarlett was very good in the offseason program and has versatility as an end/linebacker, while Eguavoen is a reliable backup. All three have special teams value.

None of Munson’s $965,000 salary is guaranteed. Of Scarlett’s $1 million salary, $450,000 is guaranteed; Eguavoen’s contract is the same as Scarlett’s.

Defensive tackle John Jenkins is at major risk; none of his $1.1 million salary is guaranteed.

Safety Clayton Fejedelem reworked his contract, lowering his salary from $2.5 million salary to $1.7 million (of which $1 million is guaranteed) and his cap hit from $2.8 million to $2 million if he’s cut. But if Wilson or Sheldrick Redwine or McKinley has an exceptional camp and preseason or someone better becomes available on waivers, then the Dolphins would need to make a decision with Fejedelem.

None of safety Rowe’s $2.5 million salary is guaranteed, but he’s still a helpful piece and cutting him would be a mistake. Butler’s $3.4 million salary isn’t guaranteed, but he’s a proven player needed behind Raekwon Davis.