SB Nation User Blog: Graham

The tRA Post

Graham — Mon, 23 Jun 2008 16:43:50 -0000

I've been promising everyone a full tRA writeup for some time now, so here it is. Enjoy.

Introduction

We don't really have a widely available coherent metric for pitchers which tells us how good a pitcher is, independent of his home park and the defence behind (and if anyone feels tempted to say 'ERA' here, read Dave Cameron's article on pitcher evaluation first). FIP and xFIP are the most commonly used general pitching stats we have, and they're not really good enough, as they only look at 3 possible outcomes of an at-bat: K, BB, HR.

There is therefore a distinct motivation for the construction of a metric which takes into account every action a pitcher is responsible for, and turns those numbers into runs, based around a highly logical and transparent mathematical framework.

Theory and Method

There are essentially only eight possibilities for the state of a baseball at the instant the contest between batter and pitcher has resolved itself. The batter may walk, strike out, or be hit by a pitch. He may also hit a line drive, a ground ball, an outfield fly, a popup, or a home run. Others, such as bunts and intentional walks, are essentially subsets of the more important outcomes. These possibilities can be regarded as being governed by the pitcher, provided that there is a large enough sample size.

tRA is built around knowing how many runs and outs each of these events are worth, and ideally we want to know this for each year so as to account for different run-scoring environments. Before we delve into the metric itself, let's see how we might accomplish this, with a little help from Matthew the Data Fairy and his magic.

Using play by play data we can, in any given year, determine the average number of outs that was made on a given type of play by simply going through logs counting outs and dividing. Fairly straightforward, although a small correction factor has to be introduced to deal with outs made on the bases. An example table for 2008 is shown below:

Runs are slightly more tricky. We have to introduce a run expectancy matrix in order to work out how many runs -should- score from any given game situation. (bases empty, no out, etc.). In general, they look something like this, but it's certainly possible to build your own based again on play-by-play data. When the matrix is derived, we can work out the difference in runs on any given play by looking at the following:

play_run_value = runs_scored + (run_expectancy_after - run_expectancy_before)

With a little effort/fairy dust, the yearly average value of each type of play can be determined. So far for 2008 it looks a little like this:

If these are combined with the frequency with which a pitcher gives up each outcome (after making some park adjustments based on these numbers [spreadsheet]) and multiplied by total batters faced (TBF), we can determine how many runs that pitcher would have given up in a neutral park in front of an average defence. From the outs table shown earlier we can also figure out how many outs/innings he would have been expected to pitch through. tRA can then be determined as follows:

tRA = expected_runs/expected_outs*27

which gives us the expected runs a pitcher will give up per 9 innings pitched.

tROA measures how many runs are saved by a given pitcher compared to an average pitcher from the same grouping (e.g. NL SP, etc.). This metric ignores the work done on determining how many outs a pitcher should be expected to record, but it does allow for measuring pitchers in terms of their overall run value (which can then be converted to wins). tRA+ is simply pitcher_tRA/league_tRA, facilitating a quick evaluation of a pitcher compared to league average.

Another point worth considering is regression towards average. Certain pitching stats are known to fluctuate quite wildly from year to year, and in order to correct for this every outcome is regressed towards the mean based on their year-by-year correlation values and the total batters that a pitcher has faced on the season, with less regression applied the larger the sample size. The actual values to which regression is applied are as follows:

K%, BB%, HBP%, GB per ball in play%, IFF per ball in air%, LD per ball in air%, and HR per FB%

The order is extremely important, as influencing GB% will have an effect on LD% later, and so on, sometimes causing regression away from the mean in unusual situations.

Once a pitcher's line has been regressed, the same algorithms used to generate tRA and tROA are applied again to give tRA* and tROA*.

Results

Unfortunately I can't give you guys any spreadsheets to play around with this time, but Matthew and I (ok, mostly Matthew) are working on making everything accesible online. We'll be sure to let you know when it's ready.

Hopefully we can appease you with some 2008 leaderboards and old 2007 player cards, though...

2007 Player Cards: Batista, Bedard, Felix, Silva, Washburn.

If there are any questions, that's what the comments section is for. Oh, and many thanks to Matthew for his work on this too.

Carlos Beltran must be destroyed

Graham — Tue, 24 Jun 2008 00:21:40 -0000

More Thoughts on Fielding

Graham — Thu, 22 May 2008 19:51:08 -0000

Well, you all know Jeff, Matthew and I all think that fielding is the most underrated aspect of baseball today. But why take our word for it? Let's talk about the importance of good glovework with a friend of mine.

This is Stephen Strasburg. He's pretty awesome, I hear.

Do people really call you that?

I'll be sure to refer to you as such in the future. So, you're a pretty damn good pitcher. How important do you think fielding is when you're on the hill?

Really? Have you never appreciated anything one of your defenders has done?

Don't you think guys who get less strikeouts might find a good defence behind them useful? Carlos Silva, for example, struck out 7.4% of the batters he faced in 2007.

No. Seven-point-four.

Uh-oh. What's wrong?

OK.

It's a strikeout bonanza!

Talking about the Mariners pitching staff. Hey, since you don't seem to mind what your fielders do behind you, how about coming to Seattle? You'd look awesome in teal! And I think we have #37 free too.

Stephen? Still there? I was asking if you wanted to play for the Mariners.

There you have it, ladies and gentlemen. Stephen 'Awesome' Strasburg doesn't care about his defence.

But I think he probably would if his K% ever dropped below like 80.

15-24

Graham — Sun, 11 May 2008 23:13:59 -0000

We won a game? I'm as confused about this as the rest of you.

Biggest Contribution: Probably Ibanez
Biggest Suckfest: Probably Batista
(If you want a real chart click here)

Miguel Batista led off the game by allowing three singles in a row, then recorded an out before yielding a Raul-assisted RBI double to AJ Pierzinski. Down 2 runs, we all knew in our hearts that the game was done and dusted, and prepared ourselves for glacially slow impending doom.

For the first time all season, the Mariners disagreed. Ichiro ripped a double down the right field line which Swisher decided to bobble, allowing him an extra base. One Cairo groundout later than the Mariners were on the board. Beltre and Ibanez went down quietly, but we had halved the ChiSox's lead.

Batista attempted to kill the momentum by putting runners at the corners with 1 down, but Johjima and Betancourt combined for one of the weirdest double plays you'll ever see. Quentin chopped a ball off the ground, Kenji snagged it, tagged the batter and threw down to second where Betancourt tagged Cabrera running from first.

Jose Lopez led off the second by rifling a pitch down the left field line for a double, and two batters later Wlad Balentien was at the plate with the based juiced and no out. Conditions were perfect for a 1-2-3 double play, and Balentien obliged, with Betancourt grounding out to end the inning.

Just as we were getting over this amazing display of offensive futility, we had runners at first and second with no outs for King Awesome, who hit a slow ground ball to short and was standing on first several years before Uribe's throw reached Konerko, thereby being called out on the little known 'you got here too quickly' rule. Squinty came out to have a bit of a chat with the umps about that but forgot what he was doing midway through the conversation and went back to the dugout for a nap.

And then Ibanez hit a bomb to right field.

And we had the lead.

And it landed ~450 feet from the plate.

This was confusing. The White Sox obviously thought so too, as they were powerless to stop Tits from having his way with them in the top of the inning, producing a flyout and two called strikes. The bottom of the inning saw Betancourt drive in Joh and Wlad with a bloop double down the right field line, and several walks later Lopez mashed a ball into left field, which Safeco chewed up and spat into the waiting glove of Carlos Quentin. Still, it was 5-2 and we didn't quite know what to do with ourselves.

Batista ran into trouble in the 6th, but Rhodes relieved him and managed to get out of the inning only giving up one run. The bottom of the inning saw Safeco say 'fuck you' to an Adrian Beltre homer to right centre, and then it stayed 5-3 for a little while, punctuated by an effective inning by Brandon Morrow, who looked great in striking out both Quentin and Thome. Kenji got a power pitch in the bottom of the 8th and turned on it for his first warning-track-flyout-which-should-have-been-a-home-run of the year (are you sensing a theme?). We got an insurance run in anyway as Swisher gifted Cairo a double, allowing Betancourt to score.

Putz came in and did his job. The fastball command was back, and although he looked a little shaky on the walk he bounced back to strike out Swisher to end the game and the Mariner losing streak.

Yaaaaay.

Points to take away:

We were mashing the ball today, and were unlucky to have only scored 6 runs.
Lopez hit the ball really well all four times he was up, with a double, two sharply hit singles, and a very long flyout.
Beltre is an unlucky bastard. Robbed by Cabrera in the first, cheated in the third, and then hit the ball very hard in his next two at bats, and only an 0-4 day to show for it.
Clement will look great for most of an at-bat and then do absolutely nothing with the last pitch. It's pretty frustrating.
I don't know how Jeff writes these things every day. He's back soon anyway and you'll get real win expectancy graphs and other assorted goodies.

Strasburg Watch

We came into today a half game ahead of the Padres for the worst record in baseball, and blew an opportunity to take the tail as they won 6-1 against Colorado. KC and San Francisco both lost the opportunity to give up ground, but Cincinnati and Washington took full advantage to pull closer to last place. We still sit a half game ahead of San Diego, with Colorado, Cincinnati, and Washington in front of us by the same margin.

It's going to be an interesting race. If we're going to be terrible, we might as well do it with some style.

14-24

Graham — Sun, 11 May 2008 02:40:55 -0000

Holy crap we are bad.

Please allow me to introduce RHP Stephen Strasburg, a sophomore starter at San Diego State University. So far this season he has struck out 40.4% of total batters faced, walked 3.7%, and allowed 0 home runs and 48 hits in 84.3 innings pitched. His FIP stands at 0.76.

Other interesting numbers:

101 (maximum fastball velocity)
1.13 (time to home plate)
0.76 (2008's FIP)
23 (number of batters struck out in start against Utah )
1 (where he will go in next year's draft)

While the Mariners enthusiastic pursuit of this young man suggests that they're doing their jobs in terms of scouting amateur talent, to be honest I'd rather we just win some games.

Edit: Incidentally, he looks like an elf . I move he be granted the nickname 'Keebler' post-haste.

Second Edit: He's not eligible for the 2008 draft, because he's a sophomore and doesn't turn 21 until July 20th, 2009 (the rules state that a player drafted out of a 4-year program must either have completed their junior year or be 21 at the time of the draft).

14-23

Graham — Sat, 10 May 2008 07:09:59 -0000

We have scored 3 runs in the past 4 games. Sometimes I'm glad I barely get to watch this team play.

Inspired by JI:

Jeff will write a real recap and throw up a chart when he gets back, and I can't be assed writing about a game I didn't see. Judging from the number of comments in the game thread, nobody else bothered with it either.

Anyone know who the #1 overall pick in 2009 is likely to be?

Season in Review, 2008

Graham — Fri, 09 May 2008 07:17:55 -0000

It sucked.

hahah facuk captain tripos

Graham — Tue, 06 May 2008 17:04:41 -0000

our greasy talons shall ensnare me no further! fuck you bitches,. none of this rmax = p[e0][s]/kmaxexp(sdkjsafjhuadjkbas) bullshit bewcaUASE IT is dfone forever. Jeff clement rules. I lovew you all apart from the people that I don't love of which there are quite a lot of peoples but you'll haqve to figure that out amongst yourelfs.

via www.geartree.com

I'm gonna get this bass. Anyone play one of these before? hwo des is sound and all that? My bass is 6 years old and pretty craptacularatstic o i need a new one and want a acoustic fretless.

Also Jeff clement fucking rules and if you don't agree thaen you can just die.

Fuck zoologists

Poll

Jeff Clement?

Roster Shakeup

Graham — Wed, 30 Apr 2008 20:08:38 -0000

Brad Wilkerson and Greg Norton have both been shown the door, according to Geoff Baker.

While I was in favour of the move prior to the season, Wilkerson had a terrible start to the year and just wasn't coming out of his slump, looking terrible the whole time - it's hardly a surprise that he's been given the boot. I suspect Norton was DFA'd over Cairo because the team envisions Jose Vidro taking the switchie pinch hitter role, because i can't imagine any other reason they'd do this.

Clement and Balentien called up from AAA Tacoma. Service time complaints are for another day. Kick some ass, boys.

One thing's for sure though - this isn't last year.

PS: I'm so glad Mike Morse is on the DL.

PPS: I'll be annoyed if Clement isn't wearing #9.

Matthew's Take: Even with Bavasi does something smart, he mucks it up.

He releases our two primary 1B backups which means Vidro is now our backup 1B.
Cairo is still on the team
12 pitchers are still on the team
You're potentially screwing yourself out of a an arb year in order to get 7 days of Clement on the roster when he's probably only going to play 3 or 4 games.

Listen, I love that they're willing to shake things up when the offense so clearly needs it (though they ignored the obvious solution, Bonds). But again, this just reeks of their total lack of planning. The Ms don't need 7 relievers, so one of them was expendable for this move; you could have just had Lowe and Morrow ride the T-Town train back and forth all year to balance their usage out.

Keeping Wilkerson around gives you at worst a 4th OF with a LH bat, which you'd want if Wlad is your new starting RF. There's zero reason to call Clement up now as opposed to 7 days from now. If you think the extra arb year doesn't matter, then you're missing the whole point. Here's what should have happened: Wlad called up, Morrow/Lowe sent down. A week hence, Clement called up, Norton DFA'd. Then you have Wilkerson as your 4th OF/ 1B backup (instead of WFB and Vidro), Vidro as your #10 hitter, Clement at DH, Wlad at RF.

[Updated] tRA Player Cards - Now Taking Requests

Graham — Thu, 10 Apr 2008 20:48:34 -0000

I've just set up my spreadsheet to generate player cards from 2007 with a bunch of useful information on them. However, I don't really have a sensible way of actually producing them all for easy viewing, so I thought I'd throw up a thread and ask who everyone wanted to take a look at. I'll start with someone dear to our hearts: King Felix.

(click for a clearer picture)

So, if anyone wants to see a particular player, go for it in the comments and I'll put a player card up. I'm bored of revision.

Note: Although I've done my best to make tRA as accurate as possible, all information has been collected by hand and thus typos are inevitable. If you see a mistake somewhere, please point it out.

Updates: Fixed a little bug in the regression algorithm that seems to be hitting the small sample size-types pretty hard, hasn't affected anyone interesting very much as far as I can tell. I've replaced Excel's automatic percentile ranking with a z-score-->% system which doesn't fit the data -quite- as well but puts the mean on the 50% mark, which I like. Also, BIP% column now in the table, pie chart's a bit bigger, and a sample size indicator is to the right of the first graph. I'm still taking requests, too.