Monday, December 26, 2016

Average Age Of The Best Players Over Five Year Periods Since 1947

Using the Baseball Reference Play Index, I found the top 10 and top 25 players in WAR for 5-year time periods starting in 1947. So 1947-51 was the first period. Then 1952-56 and so on. The table below shows these averages. The WAvg columns are the average age weighted by WAR. The two lowest averages for the top 10 were the 1957-61 periods and the 1977-81 periods.



Years
Top 10 Avg
Top 25 Avg
Top 10 WAvg
Top 25 WAvg
1947-51
30.5
29.64
30.15
29.63
1952-56
27.6
29.28
27.33
28.9
1957-61
26.6
27.62
26.59
27.25
1962-66
28.4
27.38
28.72
27.66
1967-71
29.6
28.76
29.9
29.02
1972-76
27.6
28.12
27.68
28.08
1977-81
26.1
27.56
26.25
27.48
1982-86
27.6
28
27.52
27.88
1987-91
29.1
28.32
28.97
28.38
1992-96
27.1
27.92
27.06
27.8
1997-2001
28.1
28.44
28.16
28.46
2002-06
29.8
29.56
29.8
29.74
2007-11
27.85
27.7
27.98
27.75
2012-16
27.12
28.9
27.18
28.54


The good young players from 1957-1961 were



Player
WAR
Avg Age
Hank Aaron
41.3
25
Frank Robinson
30.9
23
Al Kaline
29
24
Rocky Colavito
23.4
25


The good young players from 1977-1981 were



Player
WAR
Avg Age
George Brett
34.3
26
Gary Carter
27.4
25
Andre Dawson
26.4
24
Keith Hernandez
24.9
25
Chet Lemon
24.7
24
Willie Randolph
24.6
24
 
 

This next table shows how many of the players in the top 10 and top 25 had an average age less than 27 in each period. That means 26 or less and would include guys who were 24-25-26-27-28, so at least 2 of their seasons were at age 25 or younger. 1977-81 had six "young" players in the top 10, the most for any period. 1952-56 is second with 5. Both 2007-11 and 2012-2016 have had a large number of young players in the top 25.



Years
Top 10 < 27
Top 25 < 27
1947-51
1
6
1952-56
5
3
1957-61
4
10
1962-66
3
11
1967-71
2
7
1972-76
4
8
1977-81
6
10
1982-86
4
9
1987-91
2
8
1992-96
4
8
1997-2001
3
7
2002-06
1
5
2007-11
4
11
2012-16
2
12


This time line chart shows how many players 25 or younger had a WAR of at least 5 per team each year going back to 1946 (I used 4.75 for 154 game seasons and made similar adjustments for strike years). I did it per team since when there are fewer teams, not as many players will reach a given WAR. Baseball Reference says a WAR of 5 is an All-Star season.

It looks like the rate was pretty high for most of 1955-67. Six of those seasons were at least 0.4 and that mark has been eclipsed in only 2 seasons since then. There has been an upward trend since 2004.



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