With the Vikings' turnover in free agency and a slew of rookies added, more than a handful of positions are up for grabs on offense, defense and special teams.

Some clarity was gained during the offseason program, such as Marshall Koehn's legitimate chance to unseat Kai Forbath at kicker, but there's much to sort out for the Vikings in training camp.

Center: Third-year center Nick Easton held down the middle of the offensive line during much of spring practices and has led the competition with rookie third-round pick Pat Elflein, whom the Vikings view fits best at center after one season there with Ohio State. The Vikings moved trusty veteran Joe Berger to right guard to see how Easton and Elflein compete in what is a critical race for the retooled offensive line.

Running back: The Vikings wanted competition in the backfield and they're set up to achieve that. The offense looks destined for a committee approach with veteran Latavius Murray, rookie Dalvin Cook and Jerick McKinnon replacing Adrian Peterson. But who leads? When will Murray be healthy? He resumed running recently and, by most accounts, is expected to be ready to go by training camp after March ankle surgery. There can be roles for all three, but the most intriguing addition is the dynamic Cook, who started working with quarterback Sam Bradford more as the offseason progressed.

Slot cornerback: Captain Munnerlyn provided an underrated service for the Vikings, especially in a solid past two seasons, manning the slot for the secondary. Without him, second-year talent Mackensie Alexander is expected to take a big step forward with veteran Terence Newman also taking reps in the middle of the defense. As the Vikings found when they parted ways with Antoine Winfield before the 2013 season, it can be difficult to find a steady hand at nickel back, which plays about 60 percent of the snaps in today's NFL.

Linebacker: The other 40 percent of defensive snaps will fall at weak-side linebacker, where Edmond Robinson and Emmanuel Lamur swapped reps this offseason in the role vacated by Chad Greenway's retirement. The Vikings need to shore up the run defense, which ranked 16th in yards per carry (4.2) last season, and playing a critical role on first and second downs will be either Robinson (6-3, 245) or Lamur (6-4, 245), the biggest linebackers on the roster this side of Anthony Barr.

Kicker: The Vikings have played in at least six one-score games per season since Mike Zimmer took over and effectively lowered the water level with a renewed defense. Low-scoring and tight games enhances the role of kicker, which has been under the microscope since Blair Walsh started to go off the rails in Minnesota. So the importance of the competition between Kai Forbath and Marshall Koehn shouldn't be understated. The Vikings like Koehn's big leg, but he'll also need accuracy to get the edge on Forbath (15-15 on field goals last season).