For the first time since he missed most of the 2012-13 season with a severed Achilles tendon, Erik Karlsson hasn’t been mentioned very often when pundits are talking about the Norris Trophy. Taking a backseat to the incredible season Brent Burns is having in San Jose is one thing, but no one has really mentioned Karlsson at all.

It’s strange, because for all the quiet surrounding him while the Senators are improbably in a playoff spot, the phenom defenceman is still on pace for 70 points this season. The only talk you really hear about Karlsson right now is that his game has changed under head coach Guy Boucher.

Karlsson is by definition an attention-grabbing player, he’s dynamic in every way you can think. So, if his style of play has changed under his new coach to the point where he’s no longer a hot topic among hockey fans, that’s something worth looking into.

One thing worth noting is that his production has dropped off at even strength, going from 1.01 primary points per 60 to 0.87, and 1.57 overall points per 60 to 1.36. It’s natural to see a drop in point production after a player has had a career season, but let’s look a little deeper.

In this chart, relative turnover rates are inverted so positive means good and negative means bad.

Shockingly, Karlsson has dropped from one of the strongest possession drivers in the NHL into the negatives on a relative scale to his team, though he’s seen his goals for percentage rise at the same time.

The temptation might be to think that Boucher has made Karlsson a safer player and that has reflected in his overall on-ice goal differential, but when you look at turnover rates, you can see Karlsson is turning the puck over in dangerous areas more often than last season.

Karlsson has seen a drop in offensive zone turnovers, but the trade off of safer play in the attacking zone and more turnovers in the defensive and neutral zones is not one that leads to defensive success. His pass success rate is basically identical, though.

Another bad sign is that while Karlsson is usually one of the best in the NHL at exiting his own zone with control, he’s dumping the puck out a little more this year despite his teammates dumping it out less. This is likely the source of his increased defensive zone turnovers, since attempted dump outs from defencemen fail in the NHL nearly 40 per cent of the time.

That cross-section of changing tactics is worrying, especially Karlsson losing the possession battle, but let’s look at what he’s actually doing on the ice compared to last season to see if there’s something we’re missing.

As it turns out, Karlsson isn’t even close to the same effectiveness last season in terms of offence, and you could argue he’s worse in terms of transition play as well. The most striking changes are the drop in passes to the slot — which is a rare skill for a defenceman but one Karlsson excelled at — and controlled entries. It seems that more than anything, Karlsson has stopped carrying the puck, which seems to be a waste of his considerable talent.

On the surface, the extreme rise in pass exits and defensive zone loose puck recoveries looks like a new commitment to smart, strong defensive play from Karlsson, until you look at the fact that he’s spending 64.2 per cent of his ice time at even strength in the defensive zone this season, an absurd rise from last season’s 55.6 per cent. That isn’t to say Karlsson is playing poor defensively – he’s not. In fact, despite what anyone thinks, he has always been an extremely competent defensive player.

Top six point-producing defencemen in the NHL Brent Burns, SJ: 57

Erik Karlsson, OTT: 44

Victor Hedman, TB: 42

Duncan Keith, CHI: 38

Kevin Shattenkirk, STL: 37

Justin Schultz, PIT: 37

The considerable drop in offensive impact and puck carrying at even strength, along with the huge increase in defensive zone time, are worrying trends for the NHL’s best defenceman of the past half decade. The bottom line is that despite a rise in relative goals for percentage – which is mostly driven by the team around him getting worse — the changes Boucher has made to Karlsson’s game haven’t made him better defensively or more effective overall.

Karlsson still gets his points because he’s such a unique and dynamic player, but this isn’t the play of the best defenceman in the world anymore.

This season he may not even be in the top 10 and that’s a shame.