When the New York Rangers were able to sign defenseman Kevin Shattenkirk as a free agent last summer, it looked like a perfect move.

The Blueshirts were able to add the best available player -- a guy who played a position of need -- to a cap-friendly deal. Shattenkirk got what he wanted, too, coming to his hometown team on a relatively short four-year contract that still allows him to sneak in one more big payday.

But as turn the calendar to 2018, things are much less perfect than they seemed in July.

Roughly halfway through the regular season, almost all of Shattenkirk’s even-strength stats have dropped below his usual rates. He’s only had fewer five-on-five points per 60 minutes (0.67) and five-on-five primary points per 60 (0.38) once in his career. His Corsi For percentage -- currently sitting at 47.35% -- would be his lowest ever mark if the season ended today.

And, to make matters worse, Rangers coach Alain Vigneault called his marquee defenseman a "work in progress" before the Winter Classic.

First off, that comment needs a point of clarification. Regardless of how he is producing, Shattenkirk is not a work in progress. After 500 NHL games, he pretty much is what he is at this point. Plus, if anything, calling him a work in progress makes it seem as if the coaching staff didn’t know what to expect or currently doesn't know how to optimally use the defenseman.

While Shattenkirk hasn’t lit Madison Square Garden on fire, the issues go beyond him. At even strength, none of the Rangers defensemen are winning the possession battle. According to Corsica, Shattenkirk is only worse than one other blueliner in the top six: Brady Skjei and his 48.3% Corsi For.

The issue hasn’t been helped by the inconsistent defensive pairs, either. As illustrated by Micah Blake McCurdy’s HockeyViz, virtually every Rangers defenseman has seen time on each pair this season. Outside of the strange top pairing of Ryan McDonagh and Nick Holden, the partnerships haven’t gotten much of a chance to develop. This might be especially challenging for Shattenkirk, who has consistently gotten high-end second-pair or low-end first-pair minutes for virtually his whole career.

On the power play, however, Shattenkirk appears to be pretty much the same player he has always been. His points per 60 with the man advantage have dropped a bit to 5.78, but his 4.82 primary points per 60 would be the second-best total of his career.

The Rangers are taking 89.78% of the shots when Shattenkirk is on the ice during the power play. That’s to be expected, obviously, but it also shows that the Rangers aren’t doing anything egregiously bad that would be dragging down his numbers. He’s also shooting at a higher rate than ever before (28.44 Individual Corsi per 60, compared to 22.04 last season), although his shooting percentage has dropped a bit.

What’s the matter with Kevin Shattenkirk?

It’s just as tough to answer that as it is to understand the Rangers as a collective squad. In both cases, there’s clearly talent, but something is keeping that talent from delivering on the ice. Could the players be treated too well and lack the killer instinct, which is what Pierre McGuire suggested last season? Is Vigneault’s counter-attacking system simply a drag on the numbers of his defenders, regardless of their talent level?

Regardless, no matter what the core of the issue is, it’s not fair to call Shattenkirk a work in progress. And if he is struggling to find his footing, he’s no more of a work in progress than the Rangers' wonky line combinations and systems.