Jered Weaver’s Favorite Rockpile

One of the things we’re going to try to do more of at FanGraphs going forward is highlight good work from around the web. There’s a lot of good stuff out there, and if we can help more people see the work that’s being done, everyone wins. We’re still going to be doing our normal amount of original content, but we’ll add in some posts here and there that link out to pieces we think are worth reading. This is the first of those posts.

We’ve long known that Jered Weaver got a significant boost from pitching in Anaheim. It’s a park that significantly deflates home runs to right field, and Weaver gives up a ton of fly balls while facing a lot of left-handed hitters. The synergy between his skillset and his home park is one of the best in baseball.

Well, Jeff Sullivan pointed out this morning that there might be more to what’s going on than just a nice alignment of skills and outfield space.

I went through Weaver’s career game logs and identified 16 home starts made in the day time. One was at 3:30pm, and all the others were at or around 1:00pm. I assumed that the weather was always nice, the sun always bright.

That left 68 other home starts, almost all of which started around 7:00pm. The sample sizes here are different, but I think we have enough to make a comparison. When I put the numbers next to each other, my eyes opened wide. The numbers back up the anonymous Mariners player, and then some.

Time	Innings	Batters	ERA	BB%	K%	HR%	Contact%
Day	113	444	1.51	6.5%	28%	1.1%	71%
Night	444	1807	3.00	5.9%	21%	2.4%	79%

The fact that the data lines up with what an opposing hitter noticed instinctively by facing him in a certain situation lends some credence to the belief that this isn’t just small sample noise. It could be, of course, but it could also be that Weaver’s specific arm angle and the position of the rock pile in Anaheim combine to make it very, very hard to see the ball coming out of his hand.

It’s something to keep an eye on going forward, especially if we notice that the Angels suddenly begin to lead the league in afternoon home games.

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Dave is the Managing Editor of FanGraphs.

27 Responses to “Jered Weaver’s Favorite Rockpile”

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  1. Bryz says:

    I said this same thing on Sullivan’s post, but I’ll add it here as well. Weaver throws across his body more than any other pitcher I know.

    This would align his throwing hand with the rock pile and home plate. Sullivan pointed out that Ervin Santana doesn’t have the same splits, but Santana steps directly to the plate instead of diagonally like Weaver, so perhaps his hand doesn’t release the ball with a rock pile background like Weaver’s.

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  2. nayr mit says:

    Perhaps the angels should look into picking up Louis Coleman as their daytime setup man

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  3. George Ladeas says:

    Mitch Williams on MLB Network pointed out, Weaver significantly slows his arm speed when throwing a changeup, but because he throws across his body it is hard to pick up. Maybe the Rockpile is an added advantage.

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  4. KerryHofmeister says:

    This is why I love FanGraphs.

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  5. Smith says:

    The USS Mariner guy links to the Lookout Landing guy’s article. Ok, Marinergraphs.

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  6. Telo says:

    So, now let’s look at the rest of his daytime home starts pre 2011 instead of arbitrarily limiting our sample size because it fits a narrative. Yawn

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    • Telo says:

      Redacted. But the spirit of the post remains. We have a small sample, so let’s look at other guys with lower arm angles to test the hypothesis.

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      • Eric says:

        Ok, go

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      • Browl says:

        Well Weaver has been starting for the angels for several years and the sample is 113 innings. So to expand our sample by any meaningful amount we would need to look at starting righthanded pitchers who throw sidearm across their bodies and have played for the Angels for at least a couple years. How many of those guys do you think there are?

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    • cs3 says:

      There goes Telo again.
      In such a hurry to be a douche bag that he completely fails to realize that his complaint about “arbitrarily limiting sample sizes” was, in fact, completely off base.
      Surprise, surprise.

      Sometimes I wonder if telo arbitrarily acts like such a prick just because it fits a narrative. Yawn.

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      • cs3 says:

        Redacted. But the spirit of the post remains. With Telo’s douchiness, although his D% is very high, we have a small sample, so lets look at other guys with high D-rates to test the hypothesis.

        Or conversely, we could just look into guys who actually have something reasonable to say.

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  7. DM says:

    If you take this further- perhaps some evaluation of prime “TV matchups” and the effect on a schedule might be included. Seems to me MLB and all relevant parties benefit from Weaver facing Verlander on a Saturday afternoon- and on any given weeknight a 4pm est game with Weaver in it versus an east coast/central team also looks like a great idea for MLB/FOX/Angels regardless. Game times are certainly influenced by this.

    It’s an interesting analysis- but all in all, the numbers still look pretty great (yep I’m a bias Angel fan) for those 68 evening starts- and with over 4 times the starts in the evening – even Weaver had a few junkers.

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  8. ettin says:

    One thing that was not discussed is the mere fact that they are playing in the bright sun of Southern California. Most players will wear shades which is not a normal piece of equipment and combined with the bright So Cal sun could contribute to more pop ups especially in a pitchers park that is set up so well for Weaver.

    All of the contributing factors should be considered before pointing to the rock pile: Weaver’s cross-body motion, the bright So Cal Sun, shades, park factor, Weaver’s extreme fly ball tendencies, etc.

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    • Jake says:

      All true. Except for when a MLB player, a batter specifically, identifies Weaver in a day game as being the toughest matchup. He even states it’s because Weaver releases the ball in the rockpile and the batter can’t see it.
      It’s all explained in the original article.

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  9. DM says:

    Any word on whether this obviously LH batter is Chone Figgins? Seems like it could have been a relatively harmless statement he’d make about a guy he played with for several years. Batted .333 versus Weaver last year too- but I didn’t bother looking whether these AB were in Anaheim or not.

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  10. Damon says:

    Interesting theory, but I’m not sure I buy this. The wall in left-center is pretty low, and the rocks are pretty high, meaning that I think any RHP would be throwing with the rock pile directly behind the release point regardless of his arm angle.

    What should be done is a day/night split comparison of all Angels right handers since those rocks were added (in 1998 or something).

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  11. jesse says:

    So we are saying he’s doing ‘better’ because he has a lower ERA over 16 starts and 114 innings? Is this post serious or meant to be sarcastic?

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    • evo34 says:

      Check his lifetime home/road splits and day/night splits. They are probably the most severe (for such a large sample) in all of baseball. What’s not clear from this article is whether it is the daytime background at home, or something else that seems to make him much better at home.

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  12. DM says:

    Lifetime, 2008-2010 absolutely.

    Overall, he did actually pitch better at night last year- but his day game junker Aug 13th @TOR probably has everything to do with that difference (8 of 18 earned runs given up that day in just 8 day games overall).

    He’s always been a better away pitcher, but is trending better on this in 2011 though- and a home/away ERA split of a run isn’t exactly unique- Angels staff was .82 better at home as a whole last year. Verlander has such a home/away split the last 3 years.

    If you look at games where Weaver gives up more than 5 runs- there have been significantly more “breakdowns” on the road- He’s only had 5 such games at home since 2008 versus 14 of these games on the road.

    In 2011 there’s two games – August 13 at Toronto, August 26 at Texas that he gave up 15 earned runs combined. This out of 63 ER for the whole year.

    2010 – 4 games stand out- Boston, Oakland 2x, Texas

    2009 – NY, Bos, TEX

    2008 – SEA 2x, NY, KC, BOS

    I’d rather believe he gives it his all, sometimes gets flustered, and for whatever reasons – this is just more likely to happen in an away game (seems really laid back personally but sure can get “heated” on the mound).

    If there are a few more LH hitters that agree with the above- i.e. that the rocks give him an advantage- then I’d have no issues accepting it. Otherwise you are looking at something that could have been a “bit special” – brightness of the sun, batter height, complexion, eye shade, etc. could have all factored in. I personally doubt it adds up to much over the long haul but sure haven’t stepped in the box myself.

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  13. Rob says:

    There are so many other possible factors playing in on this:

    1.The haze layer that sits over Anaheim in the summer causes an unusual light scattering effect making it difficult for a hitter to see the seams on the ball because they’re squinting. Not many teams in the MLB (Angels, Dodgers, Padres, A’s and Giants) benefit from this weather phenomena that occurs when you’re near the Pacific Ocean with an onshore flow.

    2.Teams coming to Anaheim have the opportunity to go out on the town in L.A. the night before. This leaves the players slightly impaired going into the following day game. I don’t think I’d pass on the opportunity to be young, rich and eligible in Hollywood for a night – they make TV shows about it.

    3. Weaver has more experience pitching during the daytime in the Los Angeles area. He grew up around Simi Valley and probably pitched all of his high school games and most of his college games(LB st) during the daytime. He understands the physics of this environment better because it’s his natural environment to pitch in.

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