Most Home Runs, Season, By a Third Baseman

# HR Player, Year
1. 49 Harmon Killebrew, 1969

2. 48 Mike Schmidt, 1980

3. 47 Troy Glaus, 2000
3. 47 Eddie Mattthews, 1953

5. 46 Vinny Castilla, 1998
5. 46 Eddie Mattthews, 1959

7. 45 Chipper Jones, 1999
7. 45 Mike Schmidt, 1979

9. 43 Al Rosen, 1953
9. 43 Matt Williams, 1994

11. 42 Harmon Killebrew, 1959

12. 41 Tony Batista, 2000
12. 41 Darrell Evans, 1973
12. 41 Troy Glaus, 2001
12. 41 Harmon Killebrew, 1970
12. 41 Eddie Matthews, 1955
12. 41 Phil Nevin, 2001

18. 40 Ken Caminiti, 1996
18. 40 Vinny Castilla, 1996
18. 40 Vinny Castilla, 1997
18. 40 Eddie Matthews, 1954
18. 40 Tony Perez, 1970
18. 40 Mike Schmidt, 1983
18. 40 Dick Allen, 1966

25. 39 Harmon Killebrew, 1966
25. 39 Eddie Mathews, 1960

27. 38 Adrian Beltre, 2004
27. 38 Howard Johnson, 1991
27. 38 Chipper Jones, 2001
27. 38 Dean Palmer, 1996
27. 38 Dean Palmer, 1999
27. 38 Mike Schmidt, 1975
27. 38 Mike Schmidt, 1976
27. 38 Mike Schmidt, 1977
27. 38 Jim Thome, 1996
27. 38 Matt Williams, 1993
Source: Lee Sinins

There are 18 different players on this list.

Update: Great chart over at John's Dodger Blog showing how rare it is for a home run champion, as Beltre might be, to start the season batting seventh or lower in the lineup. Try 30 years since the last time it happened.

Update 2: Take Killebrew off the top spot - he played half the season at first base.