Tuesday, May 5, 2009

Was Kiprusoff Overworked?

I got linked recently from the CalgaryPuck forum, where they are debating whether Kiprusoff's poor numbers this season were because of him being overworked. One of the posters did a nice little study that suggests games played has little impact on the numbers, by comparing save percentages before, during, and after either a 2-season or a 3-season stretch of playing 68 or more games. There was very little difference in the results (save percentages before and after were all +/- .004 from how the goalies did in their high-workload seasons).

One criticism of this technique, however, is that even if goalie fatigue is generally overrated, Miikka Kiprusoff might still be a unique case with a specific weakness in that area. I decided to look at Kiprusoff's results to see if they can tell us anything about his workload:

I pulled the game logs for each of Kipper's last 5 seasons, and looked at the number of days between starts. Here are the overall results:

1: 2.98 GAA, .897 sv%, .565 win %
2: 2.43 GAA, .914 sv%, .626 win %
3: 2.33 GAA, .919 sv%, .636 win %
4: 2.05 GAA, .930 sv%, .635 win %
5+: 2.36 GAA, .915 sv%, .769 win %

Kiprusoff did not do very well in back-to-back starts, but performing poorly in back-to-backs is not unique to him. Teams generally do worse, so part of that is likely to be the rest of the team. If Kiprusoff got at least one day of rest between games, then he played pretty well, and he (and his teammates) did slightly better with additional rest.

Looking at the 2008-09 results, Kiprusoff played 9 back-to-back games, which is the most he played in any single season. His results: 2-7-0, 3.23, .899, suggesting that he was overworked by his coach.

I disagree, however. I think there are two reasons why this is not valid as an excuse for Kipper's overall poor play:

1. Kiprusoff did not do substantially better with 1, 2, or 3 days rest in 2008-09.

1 day rest: 24-11-2, 2.83, .904
2 days rest: 11-6-0, 2.80, .907
3 days rest: 4-2-0, 3.37, .899

2. Calgary as a team obviously played poorly in back-to-back games.

Kiprusoff faced 2.5 extra shots against in his back-to-back starts. That explains why he allowed 0.4 more goals per game with a .005 drop in save percentage. He also had a much worse record, indicating that the rest of the team didn't score much in front of him.

It would have helped Kiprusoff's stats if he didn't play in those back-to-back games. It probably wouldn't have helped the team much, though. The only difference would have been that it would have been Curtis McElhinney getting shelled instead of Kipper. Kiprusoff doesn't have a pattern of strong performance in back-to-back games, but a lot of this appears to be the effect of travel for a West Coast team like Calgary.

If we take out the back-to-backs, it is still apparent that Kipper's best days are behind him. I looked at his numbers for games with between 1 and 3 days rest over the last several seasons, to get a better comparison:

2008-09: 39-19-2, 2.88, .904
2007-08: 33-23-10, 2.61, .908
2006-07: 35-22-7, 2.45, .918
2005-06: 35-16-8, 1.90, .929
2003-04: 20-9-3, 1.61, .938

Unless there is some cumulative wear effect, it's not his seasonal workload that is the cause for Kiprusoff's poor play. He is simply getting worse.

We see the decline even when we break it down further by the number of days rest between games. Here are the seasonal save percentages from 2003-04 to 2008-09:

0 days rest: .929, .889, .901, .893, .899
1 day rest: .940, .928, .906, .907, .904
2 days rest: .927, .928, .931, .903, .907
3+ days rest: .917, .938, .946, .922, .905

To me, the numbers in the last two columns don't suggest an overworked goalie, just a mediocre one. The only year where it really looks like rest was a big help for Kiprusoff was 2006-07. I'd still bet that a lot of that was randomness, however, since the seasonal sample sizes here are pretty small.

An interesting study would be to look at shot quality results for goalies playing in back-to-back games, to see if we can better break down the responsibility of the dropoff between the goalie and the defence. Until then, I think it is likely that the blame is split between both parties, but we can't go much further than that.

Kiprusoff's numbers might have benefitted if Keenan spelled him a few times when the Flames were playing on consecutive nights, as Calgary seems to have played poorly as a team in back-to-backs this year. That does not come close to explaining his regression this year or last year. Kiprusoff hasn't been an elite goalie since 2007, and right now he's probably not even an average goalie, gaudy win totals notwithstanding. If workload has anything at all do with his results, it is far more likely to be the cumulative effects of playing a 70+ game workload for 4 years in a row rather than anything specifically related to 2008-09.


Vic Ferrari said...

The freefall is dramatic for Kiprusoff for sure.

On the back to back issue, most of those games are played on the road, and road teams generally get fewer PPs than the home squad. Probably especially so in back to back games, where the team is even more tired. So that would affect the save% quite a bit I suspect.

Semi-related, the EV stats for home and road teams in 07/08 are here.
The EVsave% of the road team drops .001 or so. The shot differential moves a bit in favour of the home team, accounting for most of the goal differential.

The extra PPs knock down the overall save% for the road goalies though, even though road ppsave% is a touch higher than at home. Home PP's may just be a smidge more shot happy.

Scott Reynolds said...

Kiprusoff is certainly struggling. His EV save percentage this year was fourth worst among goalies who played at least thirty games. He's only ahead of Raycroft, Toskala and Osgood.

Anonymous said...

So the guy is getting older, and not performing at the same level he once did, why is this surprising to people?

Kent W. said...

Because he's gone from a Vezina winning goalie to a worse than average goalie in the space of 3 seasons perhaps?

Statman said...

M.K. turned 32 at the start of the season - not ancient by any means - & has been falling off for a few yrs.

Perhaps smaller &/or lighter goalies depreciate faster. Lighter framed non-goalies like Gretzky & Lafleur fell off relatively quicker from their peaks than more physically solid players like Messier & Marcel Dionne.

Anonymous said...

Or maybe this is another case of a butterfly goalie faltering when he can no longer hide behind a good defense. It's no secret that over the past couple years Calgary has completely changed it's once hard hitting defense first philosophy to a more open run and gun transition game.

Matt said...

Oooh, sounds like someone's been anonymously watching the TSN panel, but not any actual Flames games.

The Contrarian Goaltender said...

"Home PP's may just be a smidge more shot happy."

I wonder if the guys yelling "SHOOOOT!!" have some effect. Hopefully not.

"Perhaps smaller &/or lighter goalies depreciate faster. Lighter framed non-goalies like Gretzky & Lafleur fell off relatively quicker from their peaks than more physically solid players like Messier & Marcel Dionne."

On the other hand, Eric Lindros and Cam Neely were built like tanks. I'm not convinced that size has any effect on anything with respect to longevity for goalies. But that might be worth looking into in some sort of methodical way rather than relying on anecdotes.

"Or maybe this is another case of a butterfly goalie faltering when he can no longer hide behind a good defense. It's no secret that over the past couple years Calgary has completely changed it's once hard hitting defense first philosophy to a more open run and gun transition game."

Things like these are easy to say, but they don't match what the numbers to say. Kiprusoff's decline is about as linear as you can find. Has Calgary's defensive deterioration followed the same pattern? They haven't been taking any more or fewer penalties, which is often one of the main reasons for shot quality swings. Their shots against haven't dropped at the same rate. I have shot quality estimates for all of those seasons, and the numbers for 2006, 2007, and 2008 were pretty much the same. Kiprusoff's backups have put up save percentages of .879, .895, .906, .889 in the last 4 seasons. There's basically nothing there to back up your assertion.

I can't really say I've watched Kiprusoff all that much, but even still it looks to me like he isn't the same guy he was in 2004. And I'll certainly defer to the opinions of Flames guys like Kent and Matt.

If Kiprusoff was the same average goalie in 2005-06 and 2008-09, and the difference was merely his defence, then the 2005-06 Flames would have had to have been allowing 23% easier than average shot quality and the 2008-09 Flames would have had to have been allowing 5% more difficult than average shot quality. There is zero chance that this is the case. The Flames weren't that good - Kiprusoff was. But he isn't any longer.

R O said...

I follow the Flames. Kipper definitely isn't the same guy as in '04, at all. A couple anecdotes on his decline:
- I've noticed he tends to lose his net sometimes. Or you might say he overcommits on shots. Either way, a lot of times he's unable to get across for one-timers and such. Although when he does, it results in glorious highlight reel saves :)
- He gets beat short-side or five-hole way too much these days. These are the "soft goals" that I really hate to see, especially the ones where it's 1-on-1 or 2-on-2 and the defence is mostly doing its job.

Those are just observations by my eye, and maybe faulty ones. But the proof is in the pudding.

Anonymous said...

He is probably getting arthritis in his hips from all the butterflying. (Not a dig at all butterfly goalies, just a statement of likely fact in his case.)