Don't worry about Erik Karlsson's shot rate
Erik Karlsson's shot and shot attempt rates have not been this low since he was a sophomore, but there's a reason for that.
One of the things that has defined Erik Karlsson's tenure as one of the league's best defensemen has been his ability to put shots on net. He's not simply one of the best defensemen in the league at putting shots on net -- he's one of the best players, period.
Something that caught my eye this season is that we're seeing a fairly significant dip in Karlsson's shooting -- it's his third worst season by shot attempts, and his second worst by shots, beating only his rookie year:
My first instinct was likely the same as yours -- it's been 13 games. This low-shooting stint could be simply be the inverse of that 17 game stretch in 2012-2013 when Karlsson was shooting with Ovechkin-esque frequency. And while the small sample size is indeed to blame for Karlsson's low shot count, it's not simply due to randomness - it's because within this small sample size, Ottawa simply hasn't been drawing penalties.
Ottawa has not had nearly as many power play opportunities this season as they usually do, which means Karlsson has had far less time on the man advantage, which is where he has more opportunities to take shots. Last year, he averaged 4:39 time-on-ice per game with the man advantage. This year? 2:59. When you overlay powerplay time on ice per game onto that chart I showed you earlier, it correlates with his current drop fairly well:
Looking at the chart below, you see that Karlsson is still firing as many shots per minute when he's on the powerplay -- he's just on the power play a lot less:
Factor in Erik's additional workload on the penalty-kill -- he's not going to be taking many, if any, shots while shorthanded, and playing shorthanded limits his even-strength time-on-ice -- and we have a pretty good explanation as to why we are seeing a dip in his shot rates. The randomness of the small sample size likely plays into it as well, but at the same time, it's reassuring to see that there's an explanation beyond the new coach or a drop in performance.
Accordingly, assuming that the Senators start getting more time with the man advantage, we should see Erik's shot totals move back up to their normal levels.