Wednesday, July 25, 2012

Can we expect Mitchell Johnson to get better?

It's an article of faith in Australian cricket circles that there is a well of untapped potential somewhere under Mitchell Johnson's mega-tough tattoos. The argument tends to run along the lines of:
  • Mitchell Johnson is a 'once-in-a-generation' bowler (top pick Dennis!);
  • All we need to do is wait for Mitch to realise his full potential.
This was highlighted by Chairman of Selectors, John Inverarity who noted that:
`We know how well he can bowl. That Test match against England in Perth when he got his action just right. It is in there somewhere, if we can provide the support and he can deliver than he is an outstanding player. Mitch has x-factor and of course.... Now he has to perform.'
So, can we expect a renaissance from Mitch? By awarding a contract to Johnson, Cricket Australia seems to think so. Rather than speculate on Mitch finding his X-FACTOR, I thought a more robust approach would be to see what the top fast bowlers over the last 20 years can tell us about what we can expect now from MITCH, and whether CA can expect much of a return on its investment.

I've gone to cricinfo and taken a sample of the highest wicket taking fast bowlers of the last 30 years. Effectively, to make this study, a bowler needs to have taken more than 200 test wickets and bowled a test match delivery in the 1990s. That gives a sample of almost 40 quick bowlers.

I'm interested in how many wickets that each bowler has taken by year of age. What I've come up with is a very rough aging curve for fast bowlers. This is what it looks like.

What does it tell us?
  • Fast bowlers tend to enjoy some success at a young age, some of the better quick bowlers were showing a lot of promise in their late teens to early twenties.
  • Fast bowlers have an 'injury nexus' at around 21/22 years of age. This isn't relevant to this post but it's really interesting information in light of Australia's ashes hopes being pinned to young bowlers like Pattinson and Cummins.
  • Fast bowlers peak between the ages of 25 and 28.
  • Fast bowlers tend to fall off gradually until they hit 31, and then decline much more rapidly from that point.
Mitch is 31.  His last two seasons have been disasters. So based on this rudimentary analysis, we could quickly make the case that perhaps Mitch is unlikely to get better. I'm happy to finish it there, but perhaps we would be well served to have a look at the data in a touch more detail and see whether these is still hope for Mitch. As such, I have broken the sample into three sections:

  • bowlers who had long, stable careers (about half of the sample); 
  • bowlers who found another gear in their early 30s (about 10 per cent of the sample); and 
  • bowlers that declined rapidly from their peak years (about 40 per cent of the sample). 

Mitch can't fall into that first category given his performance over the last 2 years. 

These are the business as usual quicks, that keep on going into their early thirties. They don't get better, and they don't get worse in a hurry. These guys don't really match the profile we have seen with Mitch to date, so we've thrown them out (or at least I haven't bothered putting together a chart for them). Some of them start awesome, and stay awesome into their late thirties (McGrath, Ambrose). Some start out mediocre and continue to be mediocre (Vaas, Caddick, Martin). Anyway, they don't fit the profile that we are looking for so we'll move on to the two groups that do. 

So the career profiles that we have left are the guys that got better, and the guys that got worse.

The late bloomer
The career path that we could hope for in the best case scenario, and the one that CA appears to be banking on given Johnson's inclusion in ODI squads for both England, and now Pakistan appears to be that Mitch will improve at age 31.
Out of our sample of almost 40 bowlers, only four found another gear in their early thirties as it were.

The late bloomers effectively amount to:

  • Two of the greatest fast bowlers of all time - Courtney Walsh and SIR Richard Hadlee;
  • Alan Donald who took 80 test wickets at age 32; and
  • A toiler who had the best season of his career at age 33 - go Merv!
There isn't a particularly good comparison for Mitch on this list. The first two guys on the list are two of the smartest bowlers that I have watched play the game. Bowlers who lost yards of pace and still found ways to get an ass-load of batsmen out. Alan Donald's body was spared the grind of test cricket until Apartheid was lifted in 1991 which may have helped delay his peak a bit. And Merv. I have no explanation for Merv.

The rapid decline 

This is the other category that Mitch can fit in to given his profile to date. Bowlers who fell off dramatically from 29 to 31 years of age. The sample is full of bowlers that fit this profile, but I've picked six for the chart below. These guys were good (Hoggard) to excellent for their peak years, but all of these guys were completely spent forces by 30 apart from Waqar who was gone by 31.

These careers look like good comparators for Johnson, in fact one bowler in particular has looked pretty similar.

Yep, Mitchell Johnson is a poor man's Steve Harmison. You would hope in a post-Argus world that CA would undertake this kind of analysis, but Johnson's continuing presence in the squad and my Ashes nightmares means that they probably haven't.

Ashes 2013. Get excited!


Professor Chaos said...

It's an essay. It took a while to get together. A much shorter post to follow!

SportingMind said...

This is the best thing I've ever seen. A credit to the WHAB team. It's the statistical proof we all needed to see.

Professor Chaos said...

Thanks Mind!
You'd be pretty crazy to back Johnson in the first place, but you know if CA wanted to spend half an hour on cricinfo they might come up with something like this...

Captain Carnage said...

I was going to put forth the same argument only with a lot less words, no charts/graphs, and loads more words of curse...

Your thesis was well worth the wait Professor...

Anonymous said...

Fans have been comparing him with Harmison for a couple of years now. Why is it so difficult for the powers that be to do this?

Please send this to thet selectors. Please.