I belong to a pretty nerdy Yahoo group comprised of Retrosheet enthusiasts who regularly exchange email to discuss potential errors and discrepancies they've mined from the vast and deep universe of play-by-play data that forms baseball's statistical history. It's a fairly wild and rowdy group of people, and things can get out of hand at times. Obviously I can't go into details -- but let's just say these guys really know how to party and just leave it at that.

A few days ago, one of these party animals asked the group for a list of rotations with the fewest number of different starters by a team in a season. Sean Forman, overlord of Baseball-Reference, was quick to satisfy the inquiry providing a link to his amazing play index tool which you can view HERE.

In the table you'll see the 2003 Seattle Mariners at the top -- amazingly, they're one of only five rotations since 1901 to use just five starters in a single season, and one of just two teams in the past 50 years:

Rk Year Team #SP STARTERS 1 2003 Seattle Mariners 5 Ryan Franklin / Freddy Garcia / Gil Meche / Jamie Moyer / Joel Pineiro 2 1966 Los Angeles Dodgers 5 Don Drysdale / Sandy Koufax / Joe Moeller / Claude Osteen / Don Sutton 3 1904 Boston Americans 5 Bill Dinneen / Norwood Gibson / Jesse Tannehill / George Winter / Cy Young 4 1901 Boston Beaneaters 5 Bill Dinneen / Bob Lawson / Kid Nichols / Togie Pittinger / Vic Willis 5 1901 Washington Senators 5 Bill Carrick / Dale Gear / Watty Lee / Win Mercer / Casey Patten

There are currently 45 teams to have finished the season having used only six starters, including two rotations from 2012: the Cincinnati Reds, the San Francisco Giants. Up until this weekend, the St. Louis Cardinals had only used six SP as well. With the return of Chris Carpenter this past Friday, the Cardinals are now bumped up to seven total SP on the season, where they join ranks with the current Nationals and Mariners rotations.

These "compact" rotations seem to be a trend in recent years, and medical and training advancements obviously deserve a great deal of the credit. From 1910-1950 there were just 19 cases where a team used fewer than eight SP in a season. There were 30 in the 1990's, 23 from 2000-2009, and there have been nine from 2010-2012 already, assuming none of the 2012 teams use an additional starter in these final days of the season.





Naturally, along with good health, these compact rotations also require reliability in each individual starter's performance in order to exist. Typically, If one of the starters falters for a stretch of time, their job quickly becomes some other pitcher's job. So we expect these compact rotations to have shiny numbers as a whole.

The 2012 Cincinnati Reds' starters have posted a 93 ERA- to date, with only Mike Leake posting an ERA above league-average. The Giants' starters, meanwhile, have been just a notch better than average this season at a 98 ERA- collectively. These are decent numbers for a rotation, and a lot of teams would love to have that sort of production out of their starters. But compared to other "compact rotations in recent history, the performance of the current Reds' and Giants' starters falls short of what one might come to expect:

Rotations With Fewer Than Seven SP since 1950 (sortable)

Year Name #SP ERA- IP IPGS ERA FIP K% BB% BABIP 1966 Los Angeles Dodgers 5 70 1095.7 6.8 2.70 2.45 19.0 4.7 0.284 1996 Los Angeles Dodgers 6 70 1020.3 6.3 3.50 3.83 18.3 7.6 0.287 1993 Atlanta Braves 6 75 1083.0 6.7 3.13 3.50 16.1 6.6 0.280 1974 Los Angeles Dodgers 6 78 1072.0 6.6 3.01 3.26 15.5 7.5 0.261 1993 Los Angeles Dodgers 6 80 1033.7 6.4 3.54 3.65 15.9 8.0 0.290 1972 Baltimore Orioles 6 80 1097.3 7.1 2.58 2.90 14.2 6.0 0.250 1970 Baltimore Orioles 6 80 1160.0 7.2 3.18 3.47 15.0 6.9 0.263 1999 Arizona Diamondbacks 6 81 1056.7 6.5 3.77 4.15 19.4 7.6 0.287 2001 Oakland Athletics 6 82 1022.3 6.3 3.72 3.86 17.7 6.4 0.286 1994 Los Angeles Dodgers 6 83 756.7 6.6 4.00 3.94 16.2 6.9 0.294 1977 Baltimore Orioles 6 83 1151.3 7.2 3.52 3.83 11.8 7.4 0.272 2002 San Francisco Giants 6 84 1004.3 6.2 3.83 3.94 15.4 8.1 0.288 2000 Atlanta Braves 6 84 1040.3 6.4 4.06 3.90 16.2 5.3 0.297 2003 Seattle Mariners 5 85 1026.3 6.3 3.92 4.50 15.1 7.5 0.269 1994 Houston Astros 6 85 709.7 6.2 4.10 4.20 15.7 7.4 0.305 1994 Chicago White Sox 6 85 743.7 6.6 3.91 4.24 16.6 7.7 0.284 1978 Los Angeles Dodgers 6 85 1120.3 6.9 3.21 3.36 12.7 5.9 0.277 1963 New York Yankees 6 85 1119.3 7.0 3.04 3.22 15.7 6.9 0.259 2005 Cleveland Indians 6 89 1006.7 6.2 3.96 3.99 16.4 6.4 0.285 2000 St. Louis Cardinals 6 89 1000.7 6.2 4.21 4.62 18.6 8.9 0.286 2005 Chicago White Sox 6 90 1074.0 6.6 3.75 4.10 15.4 6.1 0.279 1972 Minnesota Twins 6 90 1080.0 7.0 2.80 3.04 14.1 6.5 0.252 2004 Oakland Athletics 6 93 1030.7 6.4 4.24 4.24 15.5 8.0 0.296 1970 Los Angeles Dodgers 6 95 1049.3 6.5 3.91 3.87 13.2 6.5 0.274 2011 Milwaukee Brewers 6 98 992.0 6.1 3.78 3.73 20.6 7.1 0.292 1998 San Francisco Giants 6 101 964.7 5.9 4.72 4.65 15.7 8.2 0.294 2004 Anaheim Angels 6 102 964.0 6.0 4.69 4.43 16.1 7.4 0.301 1951 Cincinnati Reds 6 102 736.0 6.8 4.00 3.94 9.9 7.5 0.266 1982 Baltimore Orioles 6 103 1039.3 6.4 4.03 4.20 10.4 6.7 0.268 1980 Atlanta Braves 6 110 1027.3 6.4 4.12 4.02 11.6 6.6 0.278 1972 Montreal Expos 6 116 1013.3 6.6 3.72 3.42 14.2 9.0 0.272 2012 San Francisco Giants 6 98 939.0 6.2 3.72 3.80 20.5 7.8 0.284 2012 Cincinnati Reds 6 93 948 6.3 3.75 3.98 18.0 5.9 0.294

Only six of these compact rotations posted worse ERA- numbers than the 2012 Giants. Generally, we'd expect these types of rotations to feature a strong slate of starters, otherwise management finds someone else to pitch. But the Giants are in a rare position of having a starter that they were not willing to replace despite poor performance all season. Obviously, I'm referring to Tim Lincecum, who has had one hell of a nightmare season in 2012.

There had been a discussion amongst Giants management to consider replacing Lincecum in the rotation as early as June, though ultimately Bochy and Sabean decided against the idea. I imagine if Lincecum's +5.00 ERA had been coming from a pitcher that hadn't won two consecutive Cy Young awards a few short years ago, they would have had no reservations about removing him from the rotation. Similarly, San Francisco still owes a sizable amount of money to Barry Zito, whose ERA- of 110 would have likely been replaced under different circumstances as well.

The Reds rotation has been significantly better than the 2012 Giants, but there still have only been eight cases of a compact rotation having a worse mark than Cueto, Latos and company's combined 93 ERA-. I do find it interesting that the Reds don't have a particular commitment to their weakest link with Mike Leake. His salary is still at pre-arb rates, and he doesn't have a history of dominance the way Lincecum does. But Leake's 117 ERA- is dangerously close to replacement level, as evidenced by his 0.3 rWAR over 173 innings so far in 2012. The rare set of circumstances leading to a high ERA for a compact rotation in this case may simply be a lack of a better replacement for Leake. Or it's simply Dusty Baker.

The explanation for what leads to the opposite situation, or the very non-compact rotation, is obviously a lot simpler. I imagine it's not much more complicated than this, "Ok, this guy's terrible let's try this other guy. This guy's terrible, too, let's try this other guy." And so on, and so on.

The absolute worst case of this was the rotation for the upstart 1967 New York Mets, who sent twenty different pitchers to the mound to start a game that season.

Rotations With At Least 16 SP Since 1950 (sortable)

Year Name #SP ERA- IP IP/GS ERA FIP K% BB% BABIP 1967 New York Mets 20 125 975.7 6.0 4.12 3.61 14.1 7.4 0.290 1955 Baltimore Orioles 19 102 934.3 6.0 4.24 3.88 9.4 9.3 0.279 1996 Pittsburgh Pirates 18 103 910.0 5.6 4.56 4.38 15.5 6.5 0.316 1993 Cleveland Indians 18 126 884.3 5.5 5.24 4.86 12.3 8.3 0.304 1956 Kansas City Athletics 18 134 856.3 5.7 5.10 4.90 10.1 10.5 0.280 1952 Boston Red Sox 18 111 1038.7 6.8 3.83 3.83 10.8 9.7 0.273 2006 Kansas City Royals 17 133 848.7 5.2 5.84 5.48 12.0 9.3 0.314 2004 Texas Rangers 17 126 901.0 5.6 5.15 5.04 13.1 7.9 0.306 2003 Cincinnati Reds 17 125 883.0 5.5 5.75 5.16 12.3 8.0 0.310 1977 Seattle Mariners 17 127 833.7 5.1 5.04 5.12 10.6 8.3 0.285 1973 Texas Rangers 17 126 899.0 5.5 4.86 4.13 12.9 10.1 0.298 1969 Seattle Pilots 17 128 919.7 5.6 4.62 4.25 14.1 9.1 0.294 1967 California Angels 17 94 930.7 5.8 3.24 3.53 14.0 8.2 0.261 1965 Houston Astros 17 105 1029.3 6.4 3.93 3.16 14.2 4.8 0.290 1963 Washington Senators 17 129 954.7 5.9 4.32 4.15 12.2 7.1 0.275 1951 St. Louis Browns 17 140 644.3 6.3 5.29 4.90 7.5 13.0 0.292 1950 Washington Senators 17 106 985.0 6.6 4.71 4.25 8.0 10.0 0.295 2003 Texas Rangers 16 157 832.0 5.1 6.23 5.40 14.3 9.1 0.313 2002 Cleveland Indians 16 110 942.3 5.8 4.81 4.09 16.1 9.4 0.313 2000 Anaheim Angels 16 120 896.0 5.5 5.54 5.74 12.2 10.1 0.285 1996 Detroit Tigers 16 147 865.7 5.3 6.63 5.99 12.1 10.5 0.313 1992 Kansas City Royals 16 113 896.3 5.5 4.13 3.78 12.3 7.6 0.291 1990 Kansas City Royals 16 100 944.7 5.9 3.93 3.69 15.1 8.4 0.302 1989 New York Yankees 16 130 969.3 6.0 4.87 4.33 11.6 7.9 0.304 1983 Oakland Athletics 16 112 923.3 5.7 4.63 4.37 11.0 9.3 0.276 1966 New York Mets 16 118 957.3 5.9 4.15 3.88 12.2 6.6 0.284 1965 New York Mets 16 118 984.3 6.0 4.17 3.92 11.8 7.3 0.280 1964 New York Mets 16 124 1005.3 6.2 4.45 3.86 11.7 6.7 0.290 1961 Washington Senators 16 100 1029.7 6.4 4.16 3.89 10.6 8.1 0.273 1958 Kansas City Athletics 16 114 934.0 6.2 4.25 3.94 11.5 6.9 0.277 1956 Baltimore Orioles 16 101 969.7 6.3 4.28 3.44 12.7 9.0 0.287 1953 Detroit Tigers 16 121 1012.7 6.4 4.91 4.28 10.4 8.0 0.296 1952 St. Louis Browns 16 113 753.3 6.4 3.94 3.86 8.9 8.9 0.268 1951 Pittsburgh Pirates 16 135 655.0 6.1 5.15 4.64 9.3 9.7 0.290

I don't mean to bum you out on a Monday morning by ending the post with this very depressing list of poor-performing rotations, some of which you might even remember (2004 Rangers, 2006 Royals). So I feel obligated to direct you to the ERA- sort for this last table, where you will find a tiny nugget of hope buried deep within the bleakness.

In that very same year that the Mets gave starts to a record 20 different pitchers, the 1967 California Angels also gave starts to a remarkable 17 different pitchers over the course of the season. But what is fascinating about this particular ultra-non-compact note, is that the Angels rotation still managed an ERA- of 94 despite the revolving door of replacements on the mound. Considering that most of these rotations that used over 16 starters had ERA's at least 20% worse than average, that is a pretty impressive performance from the bench.

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