The Vikings' position battles this summer are mostly rooted in the rebuilt defense. Those competitions kick into another gear this week with the first 11-on-11 practices — unpadded, no-tackling sessions dubbed Organized Team Activities.

Head coach Kevin O'Connell's offense returns nearly every contributor from last season, when Minnesota scored 24.9 points per game (8th) to spearhead a 13-win season. The main question: Can they further ascend with their first-round draft pick, wide receiver Jordan Addison?

New defensive coordinator Brian Flores' inheritance isn't so rich.

Flores, the former Dolphins head coach and Patriots assistant, is leading the Vikings' first major roster overhaul on defense since the Mike Zimmer era. Last season the veteran defense under coordinator Ed Donatell ranked 31st in yards allowed.

Donatell's firing after one season marked the first seismic change, followed by six key contributors leaving in free agency or being let go: defensive tackle Dalvin Tomlinson; cornerbacks Patrick Peterson, Cameron Dantzler and Chandon Sullivan; linebacker Eric Kendricks and edge rusher Za'Darius Smith. Here are the most fluid positions to watch this summer.

CORNERBACK

The Vikings retained just two corners – Andrew Booth Jr. and Akayleb Evans – who played defensive snaps for last year's 31st-ranked pass defense. Injuries limited how much Evans and Booth could contribute. They're part of what O'Connell has called a young "nucleus" in the secondary, along with 2022 first-round safety Lewis Cine, and now third-round cornerback Mekhi Blackmon. Newcomer Joejuan Williams, a former Patriots corner, should join them in competing for two open spots. The Vikings need an outside cornerback to start opposite Byron Murphy Jr., signed in free agency. The Vikings also need a third corner to take Murphy's outside spot when he slides into the slot during nickel packages.

INTERIOR DEFENSIVE LINE

Rotational roles and maybe a starting spot in the base 3-4 defense may be up for grabs. The Vikings couldn't afford to re-sign Tomlinson, who got $25 million guaranteed at signing in Cleveland. The rest of last year's interior line remains intact and the team added former Packers interior defender Dean Lowry, who appears in line to start. The team re-signed last year's other starting defensive end, Jonathan Bullard, but he got just $50,000 guaranteed. One player to keep an eye on is Khyiris Tonga. He came on strong last year and is a massive 338-pound option to help replace the 325-pound Tomlinson. Young linemen James Lynch, Esezi Otomewo and rookie Jaquelin Roy are also in the mix.

'DIME' CORNER OR SAFETY

The Flores defense promises to bring a Patriots-like, shapeshifting counter to whichever offense shows up. That could include various defensive subpackages like "dime," or a typically pass-focused group with six defensive backs. Flores often used this look when coaching the Dolphins. Players say they're learning positions other than their own, because a corner could end up in a linebacker-type role. Booth, the second-year corner, said he's learning "every position in the back seven, because it could change based on the play call and different variations of what we do." A defensive back, like Cine or safety Josh Metellus, could carve out a role as a "dime" safety.

ROTATIONAL EDGE RUSHER

The long-anticipated Za'Darius Smith trade leaves the Vikings with Danielle Hunter and Marcus Davenport, the ex-Saints pass rusher who got $10 million guaranteed for this season. Playing time behind those starters could be shuffled depending on how they fit the new defensive approach. D.J. Wonnum (35 snaps per game in 2022) has been first off the bench; he is entering a contract season. Patrick Jones (19 snaps per game) held down the fourth spot last season. But the team made another big guarantee to an undrafted edge rusher – Army's Andre Carter II ($340,000) – a year after signing Luiji Vilain for $227,000 guaranteed after the draft. Wonnum, Jones, Vilain and Carter will compete for roles in the new defense.

GUNNER AND PUNT RETURNER

Many of the key special teams contributors – Metellus, fullback C.J. Ham, linebacker Troy Dye – return this season with coordinator Matt Daniels. But the team lost one of its best cover men on kickoffs and punts when the front office decided to let cornerback Kris Boyd leave to sign with the Cardinals. Boyd led the Vikings by playing 81.7% of special teams snaps last year, leaving a sizeable hole to fill. Defensive backs like Williams, Booth, Blackmon and Evans, and possibly some receivers could find this route onto the field. Will the Vikings have another new punt returner? Jalen Reagor underwhelmed last year, and free-agent receiver Brandon Powell most recently held down the job for the Rams.