Vikings fans might not want to ignore this preseason as much as those when quarterback Kirk Cousins was only watching from the sideline.

Two new potential starting quarterbacks will make throws during Saturday's preseason opener against the Las Vegas Raiders at U.S. Bank Stadium (3 p.m., Fox 9).

Sam Darnold and J.J. McCarthy are set to make their Vikings debuts on Saturday — in that order. Darnold will remain as the starter ahead of McCarthy, who will get a "significant" amount of playing time, according to head coach Kevin O'Connell.

But how much Darnold and McCarthy play remains to be seen. O'Connell, a former NFL backup quarterback and the Patriots' third-round pick in 2008, remembers his former coaches making promises of minutes that never came.

"I remember being guaranteed the third quarter," O'Connell said, "and as I watched the third quarter come to an end, that guarantee wasn't worth very much to me."

"For me, it's going to be a feel thing," he added. "Hey, this group's got to go another one or maybe we've seen enough, or those guys have established a little bit of a rhythm, whatever it is."

Here are five story lines to watch at U.S. Bank Stadium:

1. Darnold's composure and accuracy

There's no mistaking that O'Connell and the Vikings offensive coaches are preparing Darnold to start the Sept. 8 season opener at the New York Giants. Darnold has taken nearly all the reps with the starting offense this summer, and O'Connell said he wanted Darnold to get a "dry run" on Saturday in preparation for his next NFL start. Darnold has started just seven games the last two seasons.

"It would be great for him to go through the opportunity of preparing for the game, going through the call sheet, going through his prep, getting a dry run at that," O'Connell said Thursday.

If Darnold looks as composed and accurate as he has during training camp, he might calm some of the nerves that naturally come to an organization transitioning quarterbacks.

2. McCarthy's NFL debut

McCarthy, the youngest of six quarterbacks drafted in the first round in April, has seen more peaks and valleys during training camp. Between dart-like touchdown tosses to receivers Thayer Thomas and N'Keal Harry, like McCarthy had during a red-zone period in a practice this week, he has also forced passes into heavy traffic or missed a nearby zone defender during interceptions. McCarthy joked that he's looking forward to facing a "vanilla" defense compared to what Vikings defensive coordinator Brian Flores tosses at him during practices. Vikings fans will want to see more than a vanilla performance from their next franchise passer.

"Nothing can quite simulate real play clocks, real repercussions for things like maybe you don't do your job and it affects others or vice versa," O'Connell said. "I think it's just a really good way of seeing exactly where you're at."

3. How different will Flores' Year 2 defense look?

OK, we can't learn too much from an exhibition devoid of game planning and, at times, maximum effort. But the Vikings' defense won't just look different in Year 2 of the playbook. They retooled the depth chart, and some of those players, including linebacker Blake Cashman and rookie edge rusher Dallas Turner, are expected to play against the Raiders. Observers have been promised more aggressive man-to-man coverage, and the front office has attempted to add younger and faster talent to the roster.

4. Which cornerbacks will show up?

The Vikings are scrambling at cornerback after the death of fourth-round rookie Khyree Jackson and promising second-year Mekhi Blackmon tearing his ACL at the start of camp. They signed veteran Fabian Moreau, who immediately got first-team reps while free-agent addition Shaq Griffin (hamstring) remains out. Now, Andrew Booth Jr., in an unsurprising move, was traded to Dallas on Friday for cornerback Nahshon Wright, who won't be able to play in this exhibition. But the Vikings should get good looks at the rest of their depth, including third-year corner Akayleb Evans, Moreau, Duke Shelley, Jaylin Williams and A.J. Green III, who has made some standout plays in camp.

5. New kickoff rules are a 'can of worms'

Many fans won't recognize the NFL's new kickoff format. It'll look more like a punt. The kicking team will be at the receiving team's 40-yard line; the receiving team will have a 5-yard "setup zone" where at least nine players must stand. The setup zone is their 30- to 35-yard lines. Nobody on those lines can move until the kick hits the "landing zone," which is a requirement now, meaning every kickoff has to land inside the receiving team's 20-yard line. Kicking teams will want to avoid a touchback, which now puts the ball at the 30-yard line (up from the 25-yard line). Special teams coordinator Matt Daniels said the change, meant to revive the kickoff after it devolved into mostly touchbacks, will lead to new strategy.

"The more and more you work this new dynamic kickoff," Daniels said, "the more and more you realize how creative you can get, the can of worms it can open up."