THE BOOK--Playing The Percentages In Baseball

Thursday, November 02, 2006

Do Players Stick Around With The Same Team?

I looked at all pitchers who pitched in 1943 and 1944 for the same team.  I added up those IP in 1943 and 1944 and compared that to the total league IP.  These pitchers accounted for 64% of all IP in 1943 and 71% in 1944.  That is, 64% of all IP in 1943 were pitched by pitchers who played on the same team in 1943 and 1944.  71% were pitched in 1944 by pitchers who pitched in both those seasons.  Got it? 

I did this for all years from 1871 to 2005:

The first “stable” point was 1903.  From 1903 to 1989, it was fairly stable, with 75% of all IP pitched by pitchers who pitched for the same team in back-to-back seasons.  This number has been dropping steadily and quickly, where it is now down to 61%.  When was the last time that happened?  The turnover in 1990-2005 matches that of 1891-1902.

Note: this was a quick study, and I didn’t bother to match teams that changed locations, like Montreal/Washington, etc.  (Technically, I just matched on teamID in Lahman Database.) Someone can feel free to update this study, and to also include hitters.

I don’t know if this is a good or bad thing.  Is it better for Carlos Beltran to be a Royal for life, or a chance to be a hero for Houston and an MVP for New York?  One fan’s loss is another fan’s gain.

The more interesting look, if someone wants to do it, is to look at team winning percentages in 1990-2004, and compare it to another 15-yr period.  Is the spread in winning percentages smaller or greater these days?  Is the constant shifting of players good for competitive balance?

Ah, what the heck.

The top team from 1990-2004 was the Braves, at .595, with Tampa at the bottom at .398.  One standard deviation was .040, for teams 1990-2004.  From 1975-1989, 1 SD = .032.  1946-1960: .067.

Seems to me that the most competitve era was the free agent era, but pre the astronomical salaries.  That is, let’s take 1989.  There was 350 million$ in salaries, for 26 teams, an average of 13.5 million$ per team.  The top 10 highest paid players in 1989 averaged 2.5 million$ each, or 18.5% of the average team payroll.

In 2004, 18.5% of the average 70 million$ payroll is 13 million$.  The top 10 players in 2004 averaged 18.4 million$.

I’d be in favor of an NHL-type system, that caps off individual salaries to 20% of a standard baseline.  Chasing the extra dollar is not always good.