Friday, December 9, 2016

Left Field Smackdown: Mac Williamson vs JD Martinez

Bobby Evans and Brian Sabean all but said the Giants are done with any significant deals for this Hot Stove League season.  Both have said that at some point you have to trust your farm system to give what you need and they are comfortable with some combination of Mac Williamson and Jarrett Parker manning LF in 2017, at least to start the season.  Specifically, Bobby Evans has pointed to Adam Duvall as an example of what they don't want to see Mac doing for some other team when he could have been doing if for the Giants.  Of course, it's an open question whether Duvall ever would have put up similar numbers with the Giants, but that's another long story.

At least one prominent Giants oriented blogger is still beating the drum for JD Martinez with comments making it sound like the outcome of the 2017 season hangs in the balance of this decision and anything less than a trade for JD Martinez is tantamount to the Giants choosing money over winning.  In the process, some numbers of questionable comparability have been thrown out there making it look like Martinez is almost a sure bet to give the Giants at least 2-3 extra wins on the season which may be the difference between winning or losing the NL West.  Let's take a closer look and try our best to make sure we compare apples to apples rather than apples to macadamia nuts.

We'll start with a couple of assumptions:  1.  Both players will be full time starters and will remain injury free for a full season.  For round numbers sake, we'll say they both get 600 PA's.  2.  We'll agree that Steamer fWAR projections are a reasonable mean out of a range of possible performances for both players.

First, let's look at the raw data for both 2016 performance and Steamer projections for 2017:

JD Martinez:

2016:  .307/.373/.535, 22 HR, 9.5 BB%, 24.8 K%, fWAR= 1.8, 517 PA.
2017(Steamer):  .275/.337/.486, 27 HR, 8.0 BB%, 26.2 K%, fWAR= 1.9, 605 PA.

Yes, Martinez average fWAR for the past 3 years is close to 4, but he had a 4 and 5 fWAR in 2014 and 2015 with a sharp drop off on defense in 2016 which caused his value to plummet.  Whether he recovers his D or not is a big part of the equation for or against.  Steamer splits the difference and projects him to be merely bad in the field instead of awful.

Mac Williamson:

2016:  .223/.315/.411, 6 HR, 10.2 BB%, 27.6 K%, fWAR= 0.5, 127 PA.
2017(Steamer):  .253/.317/.413, 9 HR, 7.4 BB%, 24.3 K%, fWAR= 0.5, 284 PA.

A couple of points here.  Mac's 2016 projected to 600 PA gives him 29 HR's and an fWAR of about 2.4.  His 2017 Steamer/600 PA would give him 19 dingers per 600 PA and an fWAR of about 1.2.

Now, fWAR is supposed to be environment neutral, so we'll stipulate that based on equal PA's, Martinez mean projection would produce 0.7 more Wins than Mac.  It's not nothing, but it's a far cry from a 2-3 game difference!

Next, let's take a look at the impact of Park Factors.  Steamer's projections for 2017 assume the player will remain in the same ballpark as 2016.  Let's go ahead and accept that JD Martinez will hit 27 HR's in 2017 if he remains in Detroit, a rather dubious projection seeing as how he's only topped it once in his entire career!  Looking up Park Factors, I was surprised to learn that Comerica Park is now actually a slightly homer-friendly ballpark with a weight of 1.14 favoring HR's while AT&T Park is, by far, a fearsome HR killing machine with a weight of .700.  So, you take Martinez' projected 27 HR's, divide by 1.14 and multiply by .700 and you get a projection of 19 HR's in AT&T Park, exactly the same as Mac's 600 PA projection!  Combine that with JD's less than stellar D and it's not a good look.  Factor in the cost in prospects of trading for Martinez plus the 2017 salary difference plus the single season of control, and I don't think it's a tough decision to give Mac Williamson his big shot to be the Giants LF of the future in 2017.


  1. Wow! That's some serious, common sense analysis without the kneejerk, the sky is falling, only sexy free agents can makes the Giants better reasoning. From the outside looking in, I say give " Big Mac" Williamson a chance. I think he will do very good. If not than it can be addressed at the trade deadline or by another prospect. Baring injury, I believe the Giants are going to hit a lot better than last season. The one thing I do have any concerns about is how Belt will perform at the plate this season. He just disappeared too much last season.

  2. Doc, you had me sold on Mac a long time ago. We're at the point now where all he has to do is show it on the field. I want him to succeed like no other Giant in 2017!

  3. I may be wrong, but I seem to recall that Mac started slow in every new club and then it clicked in. I'm actually not all that worried and I think the Giants have positioned themselves very well. While their a bit thin in the farm, their strengths appear to be (in order and based on who hits when) OF, where we have a bunch of guys at AA and above, then 3b (Arroyo), then SP (Beede, maybe Blach) then relievers. Compare that to needs:

    OF--LF and then soon RF and C
    3b--Only real opening for a while
    SP--where we need one (in case Cain doesn't produce, not unlikely) this year and one next year
    RP--We're set at closer, Smith/Strickland have the 8ths, Kontos/Gearrin and Okert have the 7th, and Suarez brings up the LR. So no immediate need and chance to upgrade over time.

  4. Dr B - I've been reading you for a couple of months now and I am so impressed with your research and statistical thinking (Mac Williamson vs JD Martinez) - and your heart (Andres Torres) - you make me proud to be a Giants fan. I also grew up in Northen CA (Diablo Valley) listening to Russ Hodges and Lon Simmons - my earliest memories were camping and fishing with my grandparents and huddling around a radio every day listening to the game broadcasts. I'll never forget bat day at Candlestick!

    1. Thanks, Mooneyball. Welcome to When the Giants Come to Town!

  5. I appreciate power, but I don't fetishize it. And I prefer a 'whole player' view rather than running off after som scrub-fielding LF because he can 25-HRs in a friendly park.

    Take Michael Morse, yes he hit dingers. He hit 11 HRs as a LFer (and the rest at 1B because Belt got hurt). But he was -10 DRS in LF. Which, to me, substantially offset his HR-related run production. So lets say for a full year he'd be 25 with a -15 DRS... There's more to it (RBIs, etc.), that's for sure, but I'm looking at (in this simple model) only +10 contribution to winning.

    Whereas a really good defender with just modest power, say 15-hrs a year and a +5 to +10 DRS seems, to me at least, have a better impact on the team's fortunes as he'd be tallying-up a +20 to +25 contribution to winning. And, like I said, there's more to it and I don't enough facts to prove it. But it makes sense, to me at least, to not sell out for power if it means bringing in a fundamentally flawed player. And yet I see it happen. And I see fans demand it.

    And, even worse, with AT&T having a .704 HR park factor... For 82 games a year you're eating 100% of the fielding liability while having the HR production impacted.

    Now, of course, if he's GG in the OF and hits for average and power, yeah... That's great. But that's a whole a player, not a one-trick pony whose liabilities substantially offset his contributions.

    Which gets me to Mac. I liked what little I saw of him in the OF. He was really good replacing Pence. And RF, at AT&T, is pretty tricky from what I understand. So, to me, he's more than a big (potential) bat. I think he's got a chance to develop into something special. Doesn't mean he will... But he's got tools. And it's time to try them out. And the same goes for Parker.

    1. I'm in with this line of reasoning. Also, Fangraphs awarded Mac a 2.6 defensive fWAR credit in the third or quarter of a season he played in 2016, but Steamer pushes him down to minus 3+ fWAR defensively in their 2017 projections. Given his age and to some extent inexperience, I would expect him to perform better, not worse, defensively in 2017, and the more so if he sticks to the simpler LF in AT&T rather than, as last year, playing both LF and RF. I'm not privy to the arcane calculations by which Steamer makes such predictions, but I suggest that to the extent that Mac loses overall predicted fWAR because of defense, the forecast undervalues his likely contribution and brings him closer to the projection for Martinez.

  6. Whoops:

    Brewers righty Phil Bickford has been hit with a 50-game suspension after testing positive for a drug of abuse for the second time, as Bill Shaikin of the Los Angeles Times tweets. Bickford reportedly tested positive for marijuana before being drafted in 2015. Players on 40-man rosters are not at risk of suspension for marijuana use, but Bickford is not on Milwaukee’s big-league roster.

    1. Man, you got to be a special type of stupid to do something like that. He has potentially a golden ticket to live out any fans dream of playing in the majors and derails his progress and development by doing that. Hopefully this wakes him up.

  7. A note on the park factor: if a team signed Willie Mac, Mays, Aaron, and some sell-out-for-power type guys, couldn't they actually change their park factor? Park factor is based on stats and how they trend, right? If you got 5 guys capable of hitting 40 home runs and put them on the Giants, they might hit 30 home runs each, but it'd make the park look more "active". I could be wrong, but I was under the impression that's how park factor works.

    I bought Mac's jersey from his first home run at auction. I'm betting on it being a piece of memorabilia from a "good giant" as Kruk and Kuip would say.

    1. It would probably move the needle a bit, but it's not supposed to. Park factors are based on how both Giants and visiting players perform in AT&T Park vs other Parks in the league.

      If I remember correctly, AT&T's Park Factor took a hit after Barry Bonds left.

  8. PS: The park adjustments are only for the home parks, so impact only half the games. Giants also play games every year in LA, SD and Oakland which also suppress HR's. The only away park the Tigers visit every year that suppresses HR's is KC.