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Mat Gamel and the Defensive Break-Even Point

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Yost is gathering input from a number of different sources, including GM Doug Melvin and assistant GM Gord Ash, the club's scouting officials, coaches and young stats gurus, who Yost dubbed, "the whiz kids." He also has received input from Dave Lawson, who for years has provided deep statistical analyses for Melvin.

"I ask a lot of opinions," Yost said. "We talk to our stat people and our sabermetric people to try to put things together. They can say, 'If you hit this guy, then this guy, then this guy, you're score 15 more runs over the course of a year.' I try to take it all in and see what fits, what feels right."

This passage is from early last year, from a article discussing the benefits of batting Jason Kendall ninth. Why do I bring this up now? Well, I'm interested in how these stat gurus (or as our former affectionate nickname-caller dubbed them "whiz kids") analyze and what kind of input they have on decision making for the major league club.

I want to apply a hypothetical situation here. There are certain things we can directly quantify with stats, and then there are things that need to be left to the scouts and "baseball people". For example, I can reasonably predict how well Mat Gamel would perform as a major league hitter this year. I can also reasonably predict how well a Bill Hall and Mike Lamb platoon would perform offensively. Further advancing our knowledge of the situation, I can reasonably predict how this platoon would fare defensively, and thus overall. I could also project how well Bill Hall would fare in full-time duty. 

There is one missing variable there. We can only really guess as to how well Gamel would perform defensively at third base. So if I were a Brewer employee-- one of the "whiz kids"-- and I was assigned a project to evaluate the possible third base solutions, I could present Doug Melvin with some information showing where the break-even point would be for Mat Gamel to be the everyday third basemen. If Melvin felt Gamel would do better than my break-even number, I would reccomend that Gamel be the everyday third basemen. If not, I would advise him to start Gamel at AAA and wait to see if his defense improves.

So how would I go about finding this break-even point? I'll walk through the process here. First I need to decide on the projections to use for each hitter.

BIll Hall

BCB: .262/.329/.454

CHONE: .248/.320/.439

ZiPS: .248/.315/.445

Mike Lamb

BCB: .260/.328/.399


ZiPS: .268/.330/.389

Mat Gamel

BCB: .274/.334/.442

CHONE: .262/.328/.414

ZiPS: .260/.314/.424

I'll start with Gamel. I'm going to choose his BCB community projection, mostly because neither system has any major-league data to go on, and Gamel played hurt in the second half of last year, which likely affected his minor league numbers and adjusted his projection downward.

For Hall's full-time projection, I'll just average out CHONE and ZiPS to make a line of .248/.315/.439, which seems pretty high, but we'll go with it.

The Hall/Lamb platoon is more difficult. The BCB projections could work, but they're not totally projected for platoon performance, and I also have to figure out the amount of plate appearances versus each hand of pitcher for both players. I would imagine Hall would not be pinch hit for every time a right-handed reliever came into the game. I'm going to assume about 65% of the at-bats go to Lamb in a platoon and 35% go to Hall. For their projection, I'll average their career splits versus opposite-handed pitchers with their BCB projections. That should account fairly well for facing some like-handed pitchers, and in the case of Hall, give him a boost from his BCB projection that is quite a bit lower than his career split vRHP.

Finally, I want to create a really rough estimate of wOBA to convert to batting runs above average. We'll use OBP*2+SLG/3. It's only decent, but I can't really estimate wOBA without a full line projection of home runs, doubles, walks, and the like. This will work for the purposes here.

So here are the three Slash wOBA estimations. Please take note that the league average Slash wOBA is .360, and the actual league average wOBA is .333, so these figures are higher than you're used to seeing, but the runs above average are the same.

Gamel: .370

Hall: .354




Offensively, over 620 plate appearances:

Gamel: 5.4 runs above average, 26.4 runs above replacement

Hall: -3.4 runs above average, 17.6 runs above replacement

Platoon: Lamb -.2 runs above average, Hall 4 runs above average, 24.8 runs above replacement

Now we'll add in defense. We''ll say -10 per a full season for Lamb and +5 for Hall, so -6.5 for Lamb and a +2 for Hall in their playing time.

[Note by jihad, 01/24/09 6:22 PM CST ] I am inserting  little expansion on my defense explanation here-- it looks like I just made those numbers up. First I looked at the CHONE defense projections. Hall is projected at -1 at third, Lamb at -12. Hall has a career UZR/150 of +7 at third base and was a +6 shortstop. I feel pretty confident calling him +5. Mike Lamb is -3.6 UZR/150 in his career, is aging, and had a terrible year last year, and is trending downward. I'm calling him -10 for a full year.

So, finally,  the totals:

Gamel: 26.4 RAR, X defense

Just Hall: 17.6 RAR, +5 defense, 22.6 runs above replacement

Lamb/Hall platoon: 23.8 RAR, -4.5 defense, 19.3 runs above replacement

So Gamel with 26.4-19.3= 7.1, which is your break-even point for the platoon. If Gamel is better than -7, he's a better option than the platoon.

I personally don't know if Hall can hit .248/.315/.439 while facing righthanders every day. If he can, he would appear to be the best option, but I'll let the readers be the judge of if he can rebound to a .320ish OBP and +5 defense.  It's only three runs difference, which is definitely within the error range for this informal study. I would definitely say there's not too much benefit gained by platooning at third, though.

So Doug, if you think Gamel is a -15 defender, it wouldn't be a bad idea to at least have him start in AAA. If you think he's a -5 defender, give him the job.

[Note by jihad, 01/24/09 7:18 PM CST ] Editing again. In the comments section, Charlie Marlow asked what the break-even point would be for a Hall/Gamel platoon. I didn't consider this at first, because Gamel's splits are quite equal and platooning him would seem like a waste. But it's actually a fantastic idea. Gamel would be replacing Lamb, a below average hitter in the platoon role, with about +6 runs of production. Since we're assuming Lamb is a -10 defender in a full year and -6 in 68% of playing time, that gives Gamel a whole lot of room for sucky defense: -13 runs in 68% of playing time is the break-even point over the Hall/Lamb platoon, or around minus 16-17 runs per a full year. It doesn't seem logical at first, but Gamel provides enough of an upgrade over Hall's crappy offense vRHP or Lamb's crappy defense and offense vRHP that his margin for error goes up enough to make it feasible. The Hall/Gamel platoon also provides an opportunity to sub out Gamel late in games for defense.

So I am hereby changing my endorsement. Doug, if you think Gamel is better than a -16 defender for a full year, please call him up and platoon him with Bill E. Hall. The more I think about it, the more sense it makes. Make it happen! The full methodology is in the comments section, for those who are interested in that type of thing.