Leaf Goalies' Rebounds

So Jonathan Bernier makes James Reimer look like a pinball machine? OK, let's take a step back, here.

There is no question that goalies have to work throughout their careers on their rebound control and that some can do it better than others, but a bit of a fact checking is necessary to advance the discussion much further than that.

Analysis of rebounds is typically situational, since 1) people tend to pay attention only to rebounds that lead to shots/goals and 2) not all rebounds are created equally. But a grain of the logic that applies to statistics like Corsi and Fenwick numbers is interesting to use here, and is perhaps merits some investigation: what if all rebounds are weighted equally in the same way that shot attempts are? There is a lot of debate about the repeatability of things like Shot Quality, but if luck/randomness is the single largest factor in deciding whether a shot goes in, there is probably just as much randomness determining if a rebound is picked up by an opponent.

Some will be quick to point out that shooting percentages are only random to a point. Players do show a certain ability to repeat marginally higher shooting rates, and so perhaps goalies may show similar ranges of rebound rates. Much more data will be needed to determine if this is true, and some work has been done on this, but I find it somewhat problematic. You see, most work on the subject is done using an automated system that considers any two shots within 3 seconds of one another to be a rebound shot. But this doesn't account for all the rebounds that don't turn into a shot. This is perhaps analogous to tracking shots but not shot attempts.

So what of Reimer and Bernier? Does one goaltender play the role of 'pinball machine', churning out rebounds? Applying the concept of equal rebounds to get an answer means watching each and every shot put on net while they tend the pipes.

For the purposes of this study, a rebound is considered to be a puck which comes off the goalie after a shot, and is subsequently controlled by another player from either team. For the rebound to qualify as relevant this study (and be counted), the puck must deflect off the goalie and follow a trajectory that leads in front of the goal line. Basically, it's the foul ball rule.

For the sake of comparing the Leafs' two goalies, here are their rebound numbers to date:

If Bernier pushes 33.5% of the shots he faces back out into play and Reimer does the same with 36.8% of his, are we really talking about two goalies with a drastically different ability to control rebounds? It doesn't seem like it, but then, 1) it's only a tiny sample size and 2) this doesn't say anything about the way they distribute those rebounds. Other data on other goalies would also add very important context here.

For now, we'll just have to content ourselves with the idea that there is no objective evidence to suggest James Reimer is any worse at allowing rebounds than Jonathan Bernier. My guess is that anyone claiming he lets out way more rebounds than Bernier is leaning a little to much on anecdotal evidence.