It is difficult to accurately measure the defensive ability of NHL players, because most statistics only measure offensive achievements like goals and assists.
But with the advanced metrics wave continuing to grow in hockey circles, certain aspects of defensive aptitude are coming to the forefront.
Corsi and Fenwick ratings (described here), along with offensive/defense zone faceoff frequency, takeaways, and the old-fashioned eye test combine give a clearer picture of defensive prowess in the NHL.
This ranking is not about two-way play; offensive skill was not taken into account at all here. These are the 25 best pure defensive players in the NHL right now.