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Evaluating Nick Leddy and Johnny Boychuk with some Hockey Analytics

How good are Nick Leddy and Johnny Boychuk? We look with some hockey fancystats to see if they really are the 2nd pairing that the Isles were hoping for. Spoiler alert: You may be happy with the results.

Seen through Garth Snow's Periscope: At least, a second pairing!
Seen through Garth Snow's Periscope: At least, a second pairing!
Bruce Bennett

SB Nation 2014 NHL Preview

The Islanders acquired two D-Men long talked about as potential targets on Saturday in Nick Leddy and Johnny Boychuk. Both guys have been hyped by the media and Isles fans (and the team) as top 4 D-men, but Isles fans should know well not to take such words for granted (Andrew MacDonald, shutdown defenseman anyone?).

So who are these guys?  Let's break them down analytically (quickly).

Nick Leddy:


Table 1: Nick Leddy's stats from last year.  


Corsi%: % of all Shot Attempts (SOG+Missed Shots+Blocked Shots) taken by a player's team while they're on the ice on 5v5. A Corsi% of 50% means that each team is getting an equal amount of shots while a player is on the ice; above 50% means the team is outshooting the opponent, under 50% means they're being outshot. Corsi has been found to approximate time of possession and scoring chance #s extremely well.

Relative Corsi%: Difference in Corsi% while a player is on the ice for a team and when he is off the ice. For example, a Relative Corsi% of 5% means that the team's corsi with the player is 5 percentage points better with that player than without him - while a negative 5% means the team is 5 percentage points better in corsi with him on the bench. This measure allows us to separate a player's performance from his teammates to a certain extent.

Zone-Start Adjusted Relative Corsi:  Using a calculation from this article (each OZ faceoff adds .4 shot attempts), this is simply relative corsi once we take into account the zone-starts % a player has - so if a player is very sheltered, his ZS adjusted relative corsi will decrease, if he is buried in the DZone, it will increase.

ZS%: or Zone-Start % - The % of non-neutral zone faceoffs a player is on the ice for that are in the offensive zone at even-strength. A Higher amount (over 50%, often up to the 60%s) makes it easier for a player to post good offensive #s and less-bad defensive ones, while a lower one signifies a more defensive role that a player might have trouble scoring with.

ZS% rel: or Relative Zone-Start %: The difference between a player's zone-start % and a team's zone-start % with him off the ice. A player may have a high looking zone-start % on some teams, which would normally signify an offensive role, except some teams (really good ones) have a lot more offensive faceoffs than defensive ones, so ALL their players have high zone-starts (and some bad teams have the reverse). This allows you to put relative corsi into more perspective, as that stat also compares players to how the team does without them.

QOC TOI% - or Quality of Competition Time on Ice %: This is a measure of the competition a player faces while he's on the ice at 5v5. This measures the time on ice (in terms of % of a team's minutes) of the average opponent on the ice while a player is on the ice. A higher # means the player faced tougher competition. There is some question about how much this differs from player to player over larger sample sizes, so it might not matter as much as you'd think.

QOC TOI% - or Quality of Teammates Time on Ice %: Same thing as QOC TOI%, except it measures the quality of your teammates instead. Unlike competition, it's pretty clear this matters a LOT. A team can't control completely who each player plays against, but it CAN control who they play alongside. Again higher = stronger teammates, lower = weaker ones.

Neutral Zone Fenwick%:  A statistic rating the overall neutral zone play of the team while a player is on the ice.  Basically it shows the expected fenwick % of a player based solely upon their team's zone entries and the opponent's zone entries.

Neutral Zone Fenwick Relative%:  Like Relative Corsi, this simply subtracts the team's Neutral Zone Fenwick without a player from the team's Neutral Zone Fenwick with that player on the ice, to try and strip out the impact of teammates from a player's neutral zone fenwick.

Individual Controlled Entry %: % of a player's entries that were with "Control" - by carry-in or by pass-in. A dump-in or tip-in is an entry without control. Note that an attempted pass-in that doesn't connect is considered an entry without control.

On-Ice Entry %: The % of TOTAL entries made by both teams while a player was on the ice that are made by the Islanders. In other words, this measures which team made more entries while a player was on the ice. If there were 10 entries total while a player was on the ice, and the Isles made 6 of them, a player would have a 60% entry rate.

On-Ice Team Controlled Entry %: The % of the Isles' entries while a player was on the ice that are by carry-in. As you might expect, this is very related to a player's "Individual Controlled Entry Rate," although less so for D Men as forwards.

On-Ice Opponent's Controlled Entry %: The % of the Opponent's entries while a player was on the ice that are by carry-in. A lower # here means opponents are being forced to dump it in more often while an Islander is on the ice, so lower is better.

For Reference: All of the above stats are obtained from except for the neutral zone stats, which were obtained from Corey Sznajder and from Adam Stringham's awesome work here:


Nick Leddy is the real prize of the D-Men acquired on Saturday by the Islanders, for the simple reason that he's under team control for a while - Leddy is in the last year of a bridge deal this year, with two more RFA years after that (and that generally means a long term contract is likely).  So the Isles traded for 3+ years of Leddy, a 23 year old defenseman.  So how good is he?

Well its a bit tricky to tell.  Leddy has had fairly favorable zone starts (really favorable this last year) and thus his relative possession #s, once adjusted for them, are just a little bit positive over the last two years.  Of course, this is just a little bit positive relative to a bunch of the best D-Men in the league, so that's not really a huge negative.  Some neutral zone numbers (see this great post here) also suggest that his slightly positive relative #s are not the result of sheltering but in fact are reflective of true talent.

Potentially, more of an issue with evaluating Leddy's possession #s, is that he's spent a decent part of his time the last two years (720 minutes out of 1802) with Michael Rozsival.  That pairing of course was pretty damn dominant (61.5% corsi) and Leddy wasn't even close to that level without Rozsival.  On the other hand, Rozsival wasn't better without Leddy, so it's likely this was more a case where the two players had great chemistry together rather than Leddy (or Rozsival) being carried by the other guys.

All of this is saying that the possession #s suggest Leddy was at least not being a negative driver of possession, and may in fact be a pretty good one when compared to the rest of the league instead of to other Chicago D-Men.  And he's 23, so it's not like he can't improve - he's 10 months younger than Matt Donovan and just two months older than Calvin de Haan.

Individually, Leddy is clearly a bigtime puck moving D-Man, with him having one of the higher rates at carrying the puck into the offensive zone of any D man in Corey Sznajder's dataset (52% - comparable to Streit or Visnovsky 2013).  The on-ice data bears this out (again here) - with the Leddy and Rozsival pair being #1 in on-ice-controlled-entry%.  He's also a decent scorer, with 30 points each of the last three seasons (if you prorate the lockout season).  Course Leddy was 2nd in PP TOI last season on Chicago and that Ice time may go down if the Isles use Visnovsky at PP1 and go with 4 forwards on the PP.

Long story short: Leddy adds a puck-moving D man to the Isles who can score some points, who is likely a plus possession (although not elite possession) player, and he has at least 3 years of team control left (and probably more).  To put it shorter, he's a clear 2nd pairing D.  That's pretty damn good, especially for what we gave up.

Johnny Boychuk.


Table 2: Boychuk's stats from last year.

Boychuk is a different story than Leddy - whereas Leddy was a trade of long term asset for long term asset, Boychuk is a trade of long term assets for a short term asset - Boychuk comes with 1 year of control, and he is going to get PAID next year.  In short, Boychuk is extremely likely a rental - although unlike a trade deadline rental, the Isles will get a full year of Boychuk.  The two second rounders given up for Boychuk is a pretty standard rate for a rental D Man (Regehr, Murray, AMac (2nd and a 3rd)), so it's not an unfair deal (the conditional pick is irrelevant, since it'll only come into play if the Isles trade Boychuk to an Eastern team, and they would only do that if they got something better than a 3rd back).

Boychuk is again a very different player from Leddy in how he plays - whereas Leddy is a playmaking D-man willing to carry the puck up the ice, Boychuk is a pure defensive D Man.  And unlike many crease clearing d-men, Boychuk appears to be pretty decent - he makes the team better than when he's not on the ice, even when he hasn't played with Chara (this past year he was saddled a lot with Matt Bartkowski).  He's also by the way a right-handed D-Man, which makes him the 3rd one of those on the Isles (Hamonic, Carkner), so it would make a lot of sense for him to be playing on 3rd pair for the team (unless the team shifts Lubo to the left side, but that seems unlikely).  And Boychuk is a pretty damn good third D-Man.

Again, he's not a playmaking or offensive d man in the slightest.  He dumped the puck in a ton last year for the Bruins, which may partly have been a team effect, but was also a real indicator of his tendencies.  And that's not horrible for a D-Man (D man entries aren't the big driver of possession), and overall, he was a positive D Man in the incomplete data set we have in the neutral zone (again, see :  Capuano may talk about his big slap shot, but he's averaged under 20 points and under 5 goals per year, and didn't get PP time for a reason.


In short, the Isles obtained two very solid D-Men on Saturday, both of whom probably fit as 2nd pair D-Men.  They may be very different types of D-Men, but both will be upgrades. So, yeah: Party on Garth.