Why Mackensie Alexander's play at nickel corner is so crucial to Vikings

After limited action as a rookie last season, the Vikings are set to entrust Mackensie Alexander with the crucial nickel-cornerback role in 2017. Robin Alam/Icon Sportswire

MANKATO, Minn. -- Mackensie Alexander played 64 defensive snaps as a rookie for the Minnesota Vikings in 2016. In 2017, he likely will get the first chance to man a position that has taken on increased importance across the NFL over the past decade.

Alexander, who has received first-team snaps at nickel cornerback throughout the offseason and was with the Vikings' top defensive group in their first full-squad practice Thursday, could become something of a 12th starter this fall, as the Vikings give the former second-round pick an opportunity to replace Captain Munnerlyn.

Munnerlyn, signed in 2014 to fortify the nickel spot after the Vikings' botched experiment with Josh Robinson in 2013, had long stumped for nickel corners to be added to the Pro Bowl ballot, and was finally given his wish a year ago. It's a sign of the more lucrative opportunities available to corners who can cover slot receivers, but it's also an indicator of how heavily a player like Alexander might be counted on this fall.

As more teams use multiple-receiver sets as a de facto base offensive package, defenses have leaned heavily on their defensive-back depth over the past decade. According to ESPN Stats & Information, the frequency of NFL teams using five or more defensive backs climbed from 44.2 percent in 2007 to 59.3 percent in 2014, before dropping to 50.2 percent and 50.1 percent the past two seasons. That's mirrored a steady rise in the prevalence of offenses with three or more receivers; such sets were used 50.6 percent of the time in 2007 and jumped to 64.8 percent last season.

The Vikings' own defense has used extra defensive backs in a variety of capacities over the past decade, as schemes have changed and game situations have mandated different approaches, but the team has used at least five defensive backs no less than 47.8 percent of the time in seasons from 2007 to 2016, with an extra defensive back on the field 67.5 percent of the time in 2013. Effectively, a nickel defender can expect to be on the field for at least half of a team's snaps, and is playing plenty at the end of games when the outcome is in doubt.

Alexander's development, though, is in the estimable hands of Vikings coach Mike Zimmer, who's made a career of working with defensive backs, from Deion Sanders to Xavier Rhodes. For his part, Zimmer didn't sound worried Thursday about the situation.

"I don’t feel pressure to change the game plan," Zimmer said when asked about young players like Alexander who haven’t seen a great number of snaps in pressure situations. “We will be OK at the nickel position."

If Alexander struggles, the Vikings likely would turn to Terence Newman, who will be 39 when the regular season opens and who's been a sturdy left cornerback and occasional safety as he continues to defy expectations. Newman got some work in the slot during the Vikings' offseason program, and Zimmer earlier this week called Newman a "defensive back," not just a corner, because of all the places he can play.

The coach made it clear Thursday, though, that he sees Newman still as an outside cornerback unless the situation changes.

"Terence is a corner," Zimmer said. "That is where he is going to play, and if we need him at nickel or safety or some other spot, then we will do that, but he’s a corner."

Which means, in all likelihood, that the Vikings would turn to Alexander in a spot that's become increasingly vital over the past decade. If he succeeds -- particularly early in the season against quarterbacks such as Drew Brees and Ben Roethlisberger -- his contributions will be as significant as any in the team's defensive backfield.