2013 breaks MLB record for most extra-inning games

When the Blue Jays and Orioles went into the 10th inning Tuesday night, a new record for most extra-inning games in a single season was established. It was the 238th extra-inning game of 2013, besting the mark set in 2011 (the Diamondbacks and Padres later made it 239). No other season in MLB history featured more than 220 extra-inning contests. With five days left in the season, there's time for this season to build up a little breathing room, likely finishing up at something like 245 (I'll update this post once the final results are in). What follows is a look at some of the specifics of this year's extra innings, and how they compare to those of other seasons.

Seasons with the most extra-inning games*:

1) 2013: 239

2) 2011: 237

t3) 1986: 220

t3) 1991: 220

t3) 2007: 220

t3) 2010: 220

t7) 1996: 218

t7) 2004: 218

t9) 1977: 212

t9) 1982: 212

*The play index data from Baseball-Reference I used for this research dates to 1916, so all figures you see are from then on. Due to the shorter season and fewer teams that existed prior to then, it's unlikely there would be many changes to the data you see below, and certainly there wouldn't be any changes in the list above. This data also does not include any games that ended as ties (as was semi-common in baseball's early years). You can view the complete list I created with the play index here.

Season with the most 10-inning games: 2013 (115)

Season with the most 11-inning games: 2010 (69)

Season with the most 12-inning games: 1977, 1997, 2008 (36)

Season with the most 12-inning (or longer) games: 1992 (80)

Season with the most 13-inning games: 1992 (28)

Season with the most 14-inning games: 2011 (16)

Season with the most 15-inning games: 1963, 1975, 1976, 1980 (9)

Season with the most 15-inning (or longer) games: 1967 (20)

Season with the most 16-inning games: 1976 (7)

Season with the most 17-inning games: 1968, 1980, 1986, 1998 (4)

Season with the most 18-inning games: 2013 (4)

Season with the most 18-inning (or longer) games: 1967 (9)

2013 hasn't just set the record for most extra-inning games, it's also set a new record for most total extra innings (a 10-inning game being 1 extra inning, an 11-inning game being 2 extra innings, etc.)

Seasons with the highest number of total extra innings: 

1) 2013 (565)

2) 1980 (531)

3) 1976 (519)

4) 1982 (518)

5) 1992 (515

6) 2011 (504)

7) 1977 (491)

8) 1972 (481)

9) 1991 (477)

10) 1988 (468)

2013 is shattering that record, and will likely end up with 575-580 total extra innings by the time the season ends Sunday (or Monday).

If you divide the 565 total extra innings thus far by the 239 extra-inning games that have taken place, you get an average of 2.364 extra innings per extra-inning game in 2013.

Seasons with the highest average number of extra innings in extra-inning games: 

1) 1967 (2.698)

2) 1918 (2.593)

3) 1972 (2.586)

4) 1919 (2.573)

5) 1976 (2.569)

6) 1968 (2.563)

7) 1963 (2.562)

8) 1980 (2.541)

9) 1971 (2.472)

10) 1974 (2.453)

2013 ranks 26th on that list, with an above-average number of extra inning per extra-inning game, but not dramatically so.

There are 30 teams now and they each play a 162-game schedule. Until 1961 there were only 16 teams (and they played a shorter schedule too). It wasn't until 1998 that MLB reached it's current size, so it's to be expected that more recent seasons would have a higher number of extra-inning games. What if we look at the percentage of total games that are going extra innings, does 2013 still stand out?

Seasons in which the highest percentage of games went extra innings:

1) 1943 (13.37%)

2) 1957 (13.09%)

3) 1918 (11.73%)

4) 1942 (11.60%)

5) 1916 (11.57%)

6) 1960 (11.12%)

7) 1944 (11.05%)

8) 1965 (10.99%)

9) 1920 (10.99%)

10) 1932 (10.67%)

So far in 2013, 10.12% of all games have gone to extra innings, which ranks 17th out of the 98 seasons here. It's not a record rate, but it is the highest since 1991. The next-highest figure from the 2000s is all the way down at 34th on the list (2011, 9.76%) and no other year from the 2000s even places anywhere in the top half of the rankings.

By the time Sunday ends, we'll have gotten more innings of baseball than any season in history. I'd say that makes 2013 a great year.