March 14, 2003

Prospectus Today

Lefty-Heavy Rotations

by Joe Sheehan

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I mentioned yesterday that John Halama is the front-runner to be the Athletics' #5 starter. If he does win the job, the A's would have four left-handers in the rotation, with Halama backing up Mark Mulder, Barry Zito and Ted Lilly. Before the A's/Rockies game on Tuesday, I asked an A's executive if that imbalance concerned the team, and he said that it didn't, that quality pitching is quality pitching.

While it goes against our religion here at Baseball Prospectus to question anything the A's do, I have to admit I was curious. Is there any disadvantage to getting a disproportionate number of starts from one side or the other?

One of the best things about being back at BP--right up there with the Friday sing-a-longs and Zumsteg's lemon bars--is getting to work with people who have a strong handle on data. I asked Michael Wolverton if he could find the teams who'd gotten the greatest percentage of starts from each side of the mound. He made me promise him my lemon bars this week, but I think it was worth it. Here are the 20 teams who got the highest percentage of starts from left-handers.

Team  Year   GS-L  GS   Pct.   LgPct.   ERA  LgERA    PctLgERA

NYA   1981    85  107  .794    .357    2.90   3.66     0.79
NYA   1983   127  162  .784    .382    3.86   4.06     0.95
CHA   1975   124  161  .770    .328    3.93   3.78     1.04
CHA   1979   116  160  .725    .320    4.10   4.21     0.97
BAL   1974   116  162  .716    .362    3.27   3.62     0.90
KCA   1982   113  162  .698    .361    4.08   4.07     1.00
LAN   1965   112  162  .691    .328    2.81   3.54     0.79
BOS   1951   106  154  .688    .337    4.14   4.12     1.00
CHA   1980   111  162  .685    .364    3.92   4.03     0.97
NYA   1980   110  162  .679    .364    3.58   4.03     0.89
BAL   1977   109  161  .677    .303    3.74   4.06     0.92
ATL   1991   109  162  .673    .362    3.49   3.68     0.95
KCA   1984   109  162  .673    .340    3.92   3.99     0.98
NYA   1982   109  162  .673    .361    3.99   4.07     0.98
NYA   1994    75  113  .664    .304    4.34   4.80     0.90
CAL   1991   107  162  .660    .278    3.69   4.09     0.90
PIT   1994    75  114  .658    .276    4.64   4.22     1.10
PHI   1987   106  162  .654    .333    4.18   4.08     1.02
CAL   1994    75  115  .652    .304    5.42   4.80     1.13
SLN   1949   101  157  .643    .407    3.44   4.04     0.85

Team  Year   Pitchers

NYA   1981   May, Guidry, John, Righetti
NYA   1983   Rawley, Guidry, Righetti, Shirley, Fontenot
CHA   1975   Wood, Kaat, Osteen
CHA   1979   Kravec, Wortham, Baumgarten, Trout
BAL   1974   Grimsley, Cuellar, McNally
KCA   1982   Gura, Blue, Splittorff
LAN   1965   Koufax, Osteen, Podres
BOS   1951   Parnell, Stobbs, McDermott
CHA   1980   Burns, Trout, Baumgarten, Kravec
NYA   1980   John, Guidry, Underwood, May
BAL   1977   May, Grimsley, Flanagan
ATL   1991   Leibrandt, Avery, Glavine
KCA   1984   Black, Gura, Leibrandt
NYA   1982   Guidry, Righetti, John
NYA   1994   Key, Abbott, Mulholland
CAL   1991   Abbott, Finley, Langston
PIT   1994   Neagle, Z. Smith, Cooke
PHI   1987   Rawley, Carman, Ruffin
CAL   1994   Finley, B. Anderson, Langston, Magrane
SLN   1949   Breechen, Pollet, Brazle, Lanier

Michael concludes: "In general, the lefty-heavy staffs tend to be good staffs. Fourteen of the top 20 lefty staffs were better than average. The list is heavily weighted toward Yankee staffs, with a pitchers' park that favored lefties."

There a few shortened seasons on here. I would normally drop those, but I've left them in for completeness. The top two teams are, not surprisingly, Yankee squads from the years when Death Valley still existed: 430 feet to left-center field. Two other versions of that team, 1980 and 1982, are also on the list. The 1983 team was the only one I found whose top five starters, by games started, were all left-handed.

The two White Sox teams in third and fourth place are notable in that they turned the trick with completely different sets of pitchers (save an odd start by Ken Kravec in 1975). There are other clumps in here, including another White Sox team from that era, two Chuck Finley/Mark Langston Angels squads, and a couple of early-80s Royals rotations.

If history is any guide, the A's should have no qualms about opening the season with four left-handers in their rotation. There's no indication that teams who get the bulk of their starts from lefties operate at a disadvantage.

For completeness, let's look at the flip side. Thirty teams have gone through a season getting all their starts from right-handed pitchers:

Team  Year    GS   Pct.   LgPct.   ERA   LgERA   PctLgERA

LAN   1993   162  1.000   .696    3.50   4.04      0.87
LAN   1994   114  1.000   .724    4.23   4.22      1.00
TOR   1983   162  1.000   .618    4.12   4.06      1.01
LAN   1995   144  1.000   .719    3.66   4.18      0.88
NYN   1996   162  1.000   .769    4.22   4.22      1.00
LAN   1996   162  1.000   .769    3.48   4.22      0.82
TOR   1998   163  1.000   .732    4.29   4.65      0.92
MIL   2001   162  1.000   .219    4.64   4.36      1.07
NYA   1922   154  1.000   .206    3.39   4.03      0.84
BOS   1930   154  1.000   .241    4.68   4.64      1.01
BSN   1944   155  1.000   .221    3.67   3.61      1.02
BRO   1904   154  1.000   .133    2.70   2.73      0.99
SLN   1902   140  1.000   .157    3.47   2.78      1.25
CHN   2001   162  1.000   .219    4.03   4.36      0.93
CHN   1996   162  1.000   .231    4.36   4.22      1.03
BRO   1903   139  1.000   .146    3.44   3.26      1.06
CHN   1995   144  1.000   .281    4.13   4.18      0.99
CHN   1933   154  1.000   .213    2.93   3.33      0.88
CLE   1932   153  1.000   .269    4.12   4.48      0.92
CHN   1932   154  1.000   .249    3.44   3.88      0.89
BAL   2002   162  1.000   .254    4.46   4.46      1.00
TBA   2000   161  1.000   .250    4.86   4.91      0.99
DET   1984   162  1.000   .340    3.49   3.99      0.87
OAK   1992   162  1.000   .265    3.73   3.94      0.95
HOU   2000   162  1.000   .237    5.41   4.63      1.17
ATL   1974   163  1.000   .296    3.05   3.62      0.84
CHN   1994   113  1.000   .276    4.47   4.22      1.06

I don't think we can draw any conclusions from this. Fifteen of these teams had ERAs below the league average, but that's skewed by the Dodger Stadium teams at the top of the list.

Oh, one more thing: USC 81, Cal 77. Ya gotta believe.

Joe Sheehan is an author of Baseball Prospectus. 
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