With two weeks to go before the 2019 NFL draft, quarterback remains the Miami Dolphins' biggest question mark, but it's far from the only one. That's the life of a rebuilding team trying to take a step back in order to escape the heavy cloak of mediocrity.

The Dolphins lost four of nine 2018 Week 1 starters from along the offensive and defensive lines this offseason (Ja'Wuan James, Josh Sitton, Cameron Wake and Robert Quinn), and none of those positions has been adequately addressed through free agency. Miami needs to find four new starters (at minimum), plus improve in other areas of the trenches with its returning players.

Picking four strong starters in the draft is not a realistic task, and that's why the Dolphins have been honest about the rebuild taking multiple seasons.

Dolphins in the trenches Miami's first-round draft picks since 2010 and the total number of offensive and defensive linemen the Dolphins drafted that year: Year First-Round Pick Drafted

OL/DL 2018 Minkah Fitzpatrick, DB 0 2017 Charles Harris, DE 4 2016 Laremy Tunsil, LT 1 2015 DeVante Parker, WR 2 2014 Ja'Wuan James, RT 3 2013 Dion Jordan, DE 2 2012 Ryan Tannehill, QB 3 2011 Mike Pouncey, C 2 2010 Jared Odrick, DE 3

"We're going to obviously have an emphasis on offensive line in the draft," coach Brian Flores said. "The O-line and the run game and protection, that's near and dear to me as well. I think it's something we're definitely going to invest in, in the draft and moving forward. We're going to build this offensive line because we've got to run the ball and we've got to protect the quarterback. ... We're not there yet. I think it's pretty clear that everyone knows that. But we're going to get there."

Dolphins general manager Chris Grier has made it clear he considers the offensive and defensive lines the team's "building blocks." Left tackle Laremy Tunsil is the only established blue-chip building block in either of the trenches.

The bottom line: Miami is preparing to feast from the draft's meat and potatoes.

If the Dolphins do want their pick of trenches players, there are 10 who could be available when Miami drafts No. 13 overall: Ed Oliver (Houston, DL); Montez Sweat (Mississippi State, edge); Clelin Ferrell (Clemson, edge); Brian Burns (Florida State, edge); Rashan Gary (Michigan, edge); Christian Wilkins (Clemson, DL); Jonah Williams (Alabama OT/G); Jawaan Taylor (Florida, OT); Andre Dillard (Washington State, OT); and Cody Ford (Oklahoma, OT/G).

Miami should have its choice of multiple linemen in this group, and it would be a surprise to see the Dolphins pass on one unless they fall in love with a quarterback. A couple of those players could also be available if Miami trades back, say four or five spots, and collects more picks.

The cliché that games are won and lost in the trenches is a philosophy Grier largely believes in, and attacking the trenches in the draft isn't new for Miami. Just in this decade, the Dolphins have used their first-round pick on an offensive or defensive lineman six times (out of nine total selections). In fact, 2018 was the first Dolphins draft since at least 1966 when they didn't draft at least one player in the trenches.

But it's hard to look at the 2018 stats and 2019 roster and say that it isn't the right place to start rebuilding.

The defense gave up the most yards (6,257) in franchise history last season, finished 29th in the NFL in sacks (31) and 31st in run defense (145.3 yards per game allowed). They lost their top three pass-rushers (Wake, Quinn and Andre Branch), and their most significant addition was cornerback Eric Rowe.

Miami's top edge rushers are disappointing 2017 first-round pick Charles Harris and a collection of futures and AAF signings. The cupboard is empty.

So what are the Dolphins looking for? Defensive-line coach Marion Hobby said he wants players with "natural toughness" and an ability to play well against the run and the pass. Defensive coordinator Patrick Graham said he wants guys who are heavy-handed with good knee bend, leverage and eye discipline.

First-round prospects such as Oliver, Sweat and Wilkins check most of those boxes.

The offensive line isn't in good shape, either. The unit allowed the fifth-most sacks (52) in the league last season. Tunsil is strong, and veteran center Daniel Kilgore has the upper hand to start, but there are at least two other positions (at least one guard spot and likely right tackle) that need to be filled.

Flores has prioritized versatility, and he plans to cross-train multiple offensive linemen to see their best position. One player that will affect is Jesse Davis, who could start at right tackle (because of the loss of James in free agency) or guard, where he started for much of the past two seasons.

Dolphins offensive-line coach Pat Flaherty said the most important thing for him is being "the most physical unit on the field" and "able to will our power on opponents." That bodes well for adding first-round prospects such as Taylor and Ford.

Don't be surprised if the Dolphins double-dip at both offensive line and defensive line in this year's draft. The holes are apparent, and Grier values the trenches more than any position other than quarterback.

Filling up on meat and potatoes isn't exciting, but expect Miami to take on this method in the draft to get healthy where it's needed most.