Vikings

Can Mackensie Alexander Become a Long-Term Starter?

Mandatory Credit: Benny Sieu-USA TODAY Sports

After drafting former Central Florida cornerback Mike Hughes in the first round, it may seem like the future’s bleak for former second-round pick Mackensie Alexander. A rough rookie season and a second season without improvement might mean that Alexander will be on the outside looking in when it comes to Minnesota’s long-term plans at the position.

That said, a two-year struggle isn’t necessarily rare for cornerbacks either.

We’ve seen a good number of cornerbacks flourish right away. Recently, Tre’Davious White and Marshon Lattimore showed out as two of the best defensive backs in the NFL – not just “for rookies” but compared to all of their peers.

Casey Hayward, Richard Sherman, Darrelle Revis, Desmond Trufant and Jalen Ramsey all demonstrated high-level play as soon as they entered the league. There simply wasn’t much lead time for them to establish themselves among the league’s best.

But Vikings fans know good cornerbacks might take a while to develop. Xavier Rhodes famously struggled early in his career and so did Trae Waynes. Along with the two of them are Patrick Peterson, Darius Slay, A.J. Bouye, Stephon Gilmore, Josh Norman and Jimmy Smith.

That tells us that there’s a good deal of wiggle room when it comes to evaluating second-year corners. Naturally, the ones that play well right away are very likely to be long-term hits. But the ones that struggle early have a wider range of outcomes.

We can look at those cornerbacks through the lens of their initial two-year (regular season) PFF score and compare them to Vikings cornerbacks. For cornerbacks with only one year of play, I multiplied their grade by 1.5 to get the total as a way to price in some regression for an estimated year two grade.

I’ve added Marcus Peters as well, who many would regard as having two excellent years but ended with a middling first-year grade from PFF.

The players are sorted by “adjusted grade,” which prorates each year’s grade to 1000 snaps for that year and then sums up the total.

Player Year 1 Grade Year 2 Grade Total Grade Adjusted Grade
Casey Hayward 25.5 11.6 37.1 63.1
Chris Harris Jr. 7.4 19.8 27.2 37.1
Richard Sherman 8.4 23.8 32.2 35.0
William Jackson 15.6 23.4 33.5
Marshon Lattimore 14.5 21.75 29.0
Tre’Davious White 20.6 30.9 28.3
Darrelle Revis 5.7 22.6 28.3 26.6
Desmond Trufant 13.4 13.4 26.8 25.3
Jalen Ramsey 5 18.9 23.9 23.8
Marcus Peters -2.1 9 6.9 7.0
Xavier Rhodes 1.2 3.4 4.6 5.0
Jimmy Smith 6.5 -12.9 -6.4 -1.7
Trae Waynes -0.2 -0.6 -0.8 -2.2
Patrick Peterson -13.3 8.2 -5.1 -4.0
Stephon Gilmore -4.8 -2.9 -7.7 -8.8
A.J. Bouye -5 -1.3 -6.3 -14.7
Darius Slay -7.5 4.8 -2.7 -16.6
Josh Norman -6.1 -1.9 -8 -26.2
Mackensie Alexander -2.3 -4.4 -6.7 -48.5

In snap-adjusted terms, Alexander had an awful two years, so his case (from a PFF perspective) is distinct from other negative-score rookies.

That said, his low snap count is a big part of why his scores are so drastically different — there’s a lot of variance when measuring small-sample scores. It’s also worth mentioning that Alexander was not benched for an underperforming bench-warmer, instead losing snaps to a very well-performing Terence Newman who has been familiar with Mike Zimmer’s defense for over a decade.

Pro Football Focus scores tend to prioritize plays that a player was targeted and normalize grades for non-targeted snaps, so it might be useful to look at his statistics per snap in coverage overall to get a clearer picture.

Measure Completion Rate Yards per Reception Snaps per Target Yards per Snap
Percentile 51.3 61.0 11.3 33.4

He’s significantly worse than his peers in yards given up per snap in coverage and snaps per each target and reception, but because of his lone interception  — of Kirk Cousins, no less — he comes out ahead in any “adjusted yards” metrics, which make cornerbacks look good for preventing touchdowns and grabbing interceptions.

By using his percentile performance against his peers, we can see how well he’s performed overall — a higher number is better; it means that Alexander is better than 51.3 percent of his peers in completion rate given up.

Measure Snaps per Reception Adj. Yards per Target Adj. Yards per Snap Ball Hawk Rate
Percentile 21.1 70.8 52.1 72.3

Because interceptions tend to be fluky and Alexander’s sample size is already small, it’s likely that his yards-per-snap in coverage is a better illustration of the talent level he displayed last year.

It’s worth noting that Alexander’s high Ball Hawk Rate — which measures how often he gets his hand on the ball per every target — means he’s been aggressive in coverage, and when that’s combined with a high yards given up per snap in coverage, it might mean that he either blows coverage assignments quite a bit or gambles too often.

Pro Football Focus is not the only group of analysts that recorded worrisome statistics for Alexander. Ian Wharton watches every snap of every cornerback in the NFL and compiles his results in his cornerback handbook. Alexander ranked 35th of 36 cornerbacks in success rate — a statistic that looks at how often a cornerback wins his route, regardless of whether or not he was targeted.

Wharton’s completion rate statistic is a little more favorable for Alexander than PFF’s completion rate statistic (where he ranked as an average corner); 36.8 percent ranks sixth among his peers.

With that understood, it’s important to look at the film to see where Alexander succeeded and how he failed when he did.


After evaluating four games from Alexander, including a disastrous series of snaps against the Saints in the NFC Divisional Round game, it became relatively clear that Alexander had a specific set of problems that plagued him throughout the games instead of a broad range of issues that occasionally popped up here or there.

In some respects, this is a good thing — focusing on a few issues to resolve them should be easier than attempting to correct a large array of problems. On the other hand, it means that there are specific weaknesses that are easier for opponents to target. Not only that, it means that the kind of consistency that comes with experience won’t, by itself, be enough to showcase progress.

Alexander does do a number of things well. He’s quick to read quarterbacks and close on receivers after recognizing throws and does an excellent job closing on comeback routes in particular.

Despite his smaller stature, Alexander is also a willingly physical cornerback willing to take on and deal out contact in coverage. He also uses contact to track receivers, something that man coverage specialists like Darrelle Revis have perfected.

Alexander keeps a hand or arm in constant contact with his coverage assignment in order to anticipate movements and stay within distance of his receiver. You can see it in the below GIF, where he takes the right-side slot receiver.

His ability to quickly react to opponents — receivers or quarterbacks — does give him a leg up in both zone and man coverage. A good example comes from his game against Washington, where he starts off as a two-high safety and rotates to the slot receiver position on Cousins’ left side.

That route recognition doesn’t just apply to screens; he’s done well throughout the route stem with this skill. Below, he takes on Michael Thomas in the slot and his recognition gives him an advantage.

Like most NFL players, Alexander has more positives than negatives. He has above-average quickness, and decent speed, along with a solid gamut of skills well-suited for man coverage. Unfortunately, most NFL players lose out starting jobs because their flaws aren’t greater in number but greater in magnitude.

Alexander’s weaknesses, particularly in zone coverage, may be what makes or breaks him as a starting player for the Vikings.

The Vikings run a fairly complicated system within their zones, so it’s clear that any player in the secondary will need time and attention to detail in order to master the assignments. At the same time, errors stand out in big ways. Sometimes, Alexander doesn’t have to pay for those errors, but there are a number of instances where quarterbacks will see receivers running easily free and target his assignment.

Below, Mack is the slot corner at the bottom of the screen. He’s late to jump to his zone assignment and takes the transition for too long, leading to an easy, short completion.

That one isn’t particularly egregious, but his errors range from small to large. Below, it becomes a bigger issue.

And below, an even bigger mixup with Anthony Barr that at least didn’t result in any lost yardage. Once again, he’s at the bottom of the screen and his movement to the flat leaves a tight end completely free.

The Vikings have run this concept several times before — including on the following play — and the slot receiver needs to carry the tight end until they get to the safety’s zone.

There are also times where Alexander loses balance or loses players in recovery — issues that create problems in man and zone coverage. Not only that, his long speed can be an issue as a man coverage cornerback. Adding to that are his issues with double moves on deep routes, like below, where he covers Thomas’ post route from the slot to Drew Brees’ right.

He lost on a double move at least once in each game I viewed, often twice. While he can typically navigate the two-way go at 10-15 yards, late-breaking routes seem to give him some trouble with regard to receiver deception.

This is distinctly different from the set of problems Trae Waynes had as an up-and-coming corner, where his stiffness and inability to cover in-breaking routes created clear physical limitations that increased technical refinement allowed him to overcome. In this case, Alexander’s issues are less physical — though his deep speed will always be a liability — and more awareness and recognition-oriented.

Alexander has been a consistent liability as a tackler and won’t provide as much in run support as Newman, and certainly will look like a weaker tackler than Waynes and Rhodes. His tackling at Clemson was pretty good, so this may change as well, but for now looks like a big problem.

Projection, in that case, is difficult, though Wharton is optimistic. This is what he had to say about Alexander in his handbook:

Usually being the fourth-best cornerback and seventh-best defensive back on a unit is hardly praise, but Mackensie Alexander was in one of the most stacked depth charts in the league. Alexander split time with the immortal Terence Newman, and while that was good for the defense as Newman can still play well, it may have stunted Alexander’s opportunity to show he can develop into the next slot for the team. When he has played, he’s been decent or better. He’s a quick underneath coverage option who can get himself lost when trailing receivers across formations post-snap due to speed and awareness issues, but otherwise does a good job of pursuit and is pesky at the catch point. His 36.84% completion rate was among the top slots and his 33 yards after the catch on seven receptions is certainly respectable.

If Alexander figures out awareness inside his complicated zone assignments, there aren’t many significant weaknesses left. His ability to close down on comebacks and generally blanket underneath coverage should make him an asset despite some of the other difficulties he’s had.

With the knowledge that he beats his contemporaries in ball-hawk rate, we can presume that he can improve tremendously in coverage simply by improving in that one area — when he knows where he needs to be, he performs excellently.

Pre-draft coverage of Alexander mentioned that he might have done poorly in team interviews but many praised his overall awareness and recognition. He picked up the Clemson defense to earn a spot to start right away, but a groin injury reportedly was the only thing keeping him off the field.

With the knowledge that Alexander is an incredibly hard worker and the fact that he’s picked up defenses quickly before, there’s a good chance he could make the same turn that Rhodes and Waynes did early in their careers. But their situations aren’t the same, and those differences might be all that separates a future starter from a bench-warmer.


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