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Both pitchers go the distance

Posted by Andy on June 13, 2010

Check out how many times in the last 5 years both starters in a game pitched the whole game.

Rk Tm Opp Date #Matching
1 DET CLE 2010-06-02 2
2 LAA OAK 2010-05-14 2
3 SEA BAL 2010-04-21 2
4 NYY TEX 2010-04-16 2
5 FLA BOS 2009-06-18 2
6 KCR TOR 2009-06-07 2
7 CIN STL 2009-06-04 2
8 SFG WSN 2009-06-04 (2) 2
9 PIT CHC 2009-05-26 2
10 KCR LAA 2009-05-09 2
11 KCR TEX 2009-04-18 2
12 WSN SFG 2008-07-24 2
13 SEA OAK 2008-07-08 2
14 WSN ARI 2008-05-31 2
15 STL NYM 2007-06-27 2
16 MIN OAK 2007-06-02 2
17 SEA OAK 2007-04-25 2
18 LAA SEA 2006-08-28 2
19 KCR TOR 2006-08-26 2
20 COL SEA 2006-06-30 2
21 NYM PHI 2006-05-11 2
Provided by Baseball-Reference.com: View Play Index Tool Used
Generated 6/12/2010.

I'm stunned that it has happened so often. There were 7 such games in 2009 and already 4 in 2010.

Let's do a little math to see if this makes sense.  From 2006 through 2009, there have been 544 complete games thrown. That's out of about 19,440 game starts, a rate of 2.8%. The odds of any single game, therefore, having both pitchers pitch a complete game in the same game should be 2.8% of 2.8%, or 0.0784%. One season has 2,430 games, and 0.0784% yield an expected number of games of just 1.9 in a season.

So, I'm correct to think that 5 or more such games in a season is a surprise. It probably means that the events of both starting pitchers completing the game are not independent events--in other words some of the factors that lead to one pitcher completing the game also help the other pitcher complete his game. These might include:

  • Weather: cold temperatures, wind blowing in, and rain all tend to limit offense and help both pitchers
  • Offense: if one team scores a lot of runs, especially in one inning, this would tend to knock out the opposing team's pitcher. However, it also can knock out their own pitcher, who might be pinch-hit for in a good scoring opportunity or who might simply be pulled after sitting on the bench for a long time while he waits for his turn to pitch the next half-inning. Therefore, low scoring helps keep both pitchers in the game.
  • 8-inning complete game: if a team loses on the road, it's starting pitcher can get a complete game (loss) by throwing only 8 innings since the home team doesn't bat in the bottom of the ninth. If the home team's pitcher is throwing a complete game, there's a good chance that they are winning, making it a little easier for the visiting team's pitcher to do it too since he need go only 8 innings.

So I conclude that at least these days, complete games are not randomly distributed--at least not entirely. If one pitcher throws a complete game, there's a slightly better chance that the opposing team's pitcher does it too.

Related posts:

    Go The Distance
    Pitchers used in wins vs losses
    Most Pitchers in a Game
    HR by relief pitchers
    Using 11+ Pitchers In One Game

This entry was posted on Sunday, June 13th, 2010 at 7:21 am and is filed under Game Finders. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

12 Responses to “Both pitchers go the distance”

  1. David G Says:
    June 13th, 2010 at 7:43 am

    Another factor could be a generous strikezone. If the umpire is calling a lot of strikes then it's more likely each pitcher can keep his pitchcount down and get through more innings.

  2. Zeke Says:
    June 13th, 2010 at 8:11 am

    14 of the 21 are DH games.

  3. Brett Says:
    June 13th, 2010 at 8:18 am

    ....and some of these are rain-shortened games

  4. John Says:
    June 13th, 2010 at 8:21 am

    Also, teams often work their rotations so that aces face aces. I'd be interested to see how often the #1 or 2 starter pitches a CG compared with the 4 or 5, and then look at those games again to see if they skew towards the front of the rotation.

  5. Raphy Says:
    June 13th, 2010 at 8:34 am

    My thoughts were the same as Brett's. Of those 21 double CG only 15 of them involved both pitchers throwing at least 8 innings ( http://bbref.com/pi/shareit/9CrPr ). My guess is that if you remove rain shortened games from the equation the frequency of double complete games will fall in line with the number you would expect.

  6. Raphy Says:
    June 13th, 2010 at 8:50 am

    Here is a quick and dirty chart with games under 8 complete innings removed. Double complete games of 8 or more innings occur at a lower rate than would be expected simply by calculating the odds based on regular complete game rates. You can see this by comparing the last 2 columns in the table. I think we can conclude that the overall spike in double complete games is solely attributable to rain-shortened games.

    Total CG Double CG CG/Total (CG/Total)^2 DoubleCG/Total
    Total Games 2006-2010 21304 613 21 0.028773939 0.00082794 0.00098573
    Games with Team IP >=8 21242 587 15 0.027633933 0.000763634 0.000706148
    Games with Team IP <8 62 26 6 0.419354839 0.175858481 0.096774194
  7. Andy Says:
    June 13th, 2010 at 9:40 am

    Good detective work, folks. Thanks.

  8. Johnny Twisto Says:
    June 13th, 2010 at 11:16 am

    John, do you have evidence that aces face aces more often? These days, teams hew pretty close to a set rotation, and once teams start having off-days, I think the way any two rotations match up is random. Occasionally a manager may juggle the rotation to have a SP face or avoid a particular team, but I don't think the opposing team's likely SP comes into play much.

  9. Frank Clingenpeel Says:
    June 13th, 2010 at 11:21 am

    I believe that the DH variable is more significant. A manager would have more of a tendency to pull a pitcher in a close game if he comes top bat, especially with the game on the line.

  10. groundball Says:
    June 13th, 2010 at 5:35 pm

    Indeed, that is a benefit to the DH, not having to juggle having to PH for a pitcher.

  11. Johnny Twisto Says:
    June 13th, 2010 at 5:45 pm

    I'd say that's a detriment of the DH.

  12. Jim Says:
    June 14th, 2010 at 11:05 am

    I agree, a manager doesn't have to "manage" if he doesn't have to make a crucial decision to take is pitcher out for a batter in 6th inning of a 1-0 game

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