Question No. 4

Will the Mike Wallace trade pay off this season?

With Cordarrelle Patterson disappointing, Greg Jennings not living up to his contract and their top receiver being Charles Johnson, who they plucked off a practice squad in-season, the Vikings' biggest offseason move was the trade for Mike Wallace.

The speedy receiver never topped 1,000 receiving yards before wearing out his welcome in Miami after two seasons, although he did have 10 TDs in 2014.

It's early, but Wallace seems rejuvenated here and he clicked with quarterback Teddy Bridgewater in spring workouts, giving hope that the Vikings have found the dangerous deep threat they lacked.

Question No. 5

Will the subtle offensive line changes pay off?

Only four teams allowed more sacks than the Vikings last season and they produced inconsistent results in the running game. So what did they do about it?

The changes were hardly sweeping. They let left guard Charlie Johnson walk, used a trio of late-round picks on linemen and moved right guard Brandon Fusco over to the left.

The key to a turnaround will have to be improved health and better play from the four returning starters, particularly left tackle Matt Kalil. Slowed by knee injuries and repeatedly bested by pass rushers, Kalil could be down to his last chance.

Question No. 6

Who will start for the vikings in the secondary?

The Vikings showed tremendous improvement against the pass in head coach Mike Zimmer's first season, climbing from 31st to seventh. But despite the return of all five starters from 2014, the defensive back depth chart is far from settled.

At cornerback, veteran newcomer Terence Newman will compete with top pick Trae Waynes and returning starter Captain Munnerlyn to start opposite Xavier Rhodes.

Harrison Smith is one of the league's top safeties, but who will line up next to him? Robert Blanton and Andrew Sendejo are back, but the Vikings hope Antone Exum seizes the job.

Question No. 7

Can Anthony Barr pick up where he left off last Year?

Some draft analysts were surprised when the Vikings gambled on Barr with a top-10 pick, but it didn't take long for the big, athletic linebacker to make the Vikings look smart.

Zimmer showcased Barr in his 4-3 scheme and Barr made 70 tackles, forced two fumbles, recorded four sacks and generated NFL Defensive Rookie of the Year consideration before a knee injury ended his season in November.

Barr did not suit up in spring practices until June's minicamp because of a different injury, so he is going to have a lot of rust to work off in Mankato.

Question No. 8

Does Brian Robison have anything left in the tank?

The ninth-year defensive end and fan favorite had a down season by his standards, recording only 4.5 sacks, his lowest total as a starter.

The Vikings brought Robison back for 2015, but the 32-year-old missed much of the spring because of a pectoral injury, creating opportunities for youngsters Scott Crichton and Danielle Hunter.

It's unclear if Robison will be good to go for the start of training camp, but the Vikings need him to bounce back and help Everson Griffen bring down opposing quarterbacks. If he doesn't, this could be his last season in Minnesota.

Question No. 9

Will Kyle Rudolph prove that he can stay healthy?

Given offensive coordinator Norv Turner's history with tight ends, Rudolph was expected to have a breakout 2014 season. But he missed seven games because of injuries and finished the season with only two touchdowns.

Rudolph, who also sat out eight games in 2013, is well aware he has been slapped with the injury-prone label, so he focused on changing his conditioning and increasing his flexibility this offseason in the hope of staying healthy.

The Vikings bolstered their depth with fifth-round pick MyCole Pruitt, who had a strong spring. But a healthy Rudolph remains their best option.

Question No. 10

Who will be this season's Adam Thielen?

Thielen caught the eyes of fans and beat writers with a strong showing during last year's training camp. The Vikings liked what they saw from the wide receiver, too, giving a roster spot to the former undrafted free agent and practice-squad player.

Thielen was the latest of a long line of players who seemingly came out of nowhere to make the team. So who is it going to be this year?

Maybe undrafted rookie safety Anthony Harris? What about Babatunde Aiyegbusi, the big tackle from Poland? Or former Canadian Football League linebacker Brian Peters? Place your bets now.

Question No. 11

Can Eric Kendricks be a three-down playmaker?

Plenty of attention will be paid to Waynes, but the rookie with the clearest path to a starting gig is the team's second-round pick.

Kendricks was a tackling machine at UCLA, and despite his lack of ideal size, the Vikings had him running with the first-team defense often this spring, ahead of Audie Cole. He looked good, but he was in shorts.

If Kendricks continues to look the part when in pads, he should lock down a starting middle linebacker role and could potentially nudge veteran Chad Greenway off the field on passing downs, too.

MATT VENSEL