THE BOOK--Playing The Percentages In Baseball

Wednesday, October 03, 2007

All you need is 4 or 5 pitchers

Derek Zumsteg says:

In this playoff format, though, it doesn’t matter: they can ride those two starters, those two relievers all series long, because with all the rest days they don’t need a deep staff.

I was thinking the same thing, that with off-days galore, this is what’s going to happen.  (Well, not exactly that, but at least fewer pitchers than in the recent past.) We’ll know at the end of the series, but we’ll need a basis for comparison.  So, until then, here’s what has happened since 1969:

This represents the complete postseason totals of the 2 teams that met in the World Series, in each year.  The “n” is the total number of pitchers uses.  The “n5percent” is the total number of pitchers who threw in at least 5 percent of the innings or pitched in at least 40% of the games.  In a full season (162 G x 9IP), 5% would represent 73 IP, and 40% would represent 65 games.  That seems like a reasonable cutoff point.  Even if some closers will pitch fewer than 73 IP in the regular season or less than 65 games, they will certainly exceed those levels in the post-season.

In the last 10 years, 153 pitchers pitched for the teams in the World Series that met the above threshholds.  That’s 15.3 pitchers per year, or a bit under 8 pitchers per team.  Check out the difference with 1969-1974.

year n n5percent
1969 15 9
1970 18 11
1971 20 12
1972 16 12
1973 15 11
1974 13 10
1975 19 15
1976 16 12
1977 17 12
1978 18 14
1979 19 14
1980 17 14
1982 17 13
1983 15 13
1984 17 14
1985 17 16
1986 16 12
1987 18 14
1988 19 13
1989 18 13
1990 19 12
1991 19 15
1992 20 13
1993 20 15
1995 21 14
1996 20 14
1997 22 16
1998 19 14
1999 20 13
2000 21 17
2001 21 14
2002 22 16
2003 22 16
2004 23 17
2005 22 14
2006 22 16