This is not a ranking of the best bullpens but a selective study of great or well-reputed bullpens. The kernel of the post is concerned with how much a bullpen's greatness comes from a single pitcher.
The sortable table below list team seasons along with the SPAR those teams' bullpens had that season. Post 380 defines this method of assessing bullpens. The next columns list the top reliever in each team's bullpen, determined by SPAR. The final column lists the fraction of the teams' bullpen SPAR that is accounted for by the best reliever.
|Team||SPAR||Events||RVL||Top Reliever||TR SPAR||SPAR %|
|1999 Yankees||7.3||1936||28||Mariano Rivera||2.5||0.340|
|1990 Reds||8.1||2049||30||Rob Dibble||3.0||0.372|
|1975 Reds||7.6||1902||31||Rawly Eastwick||2.4||0.315|
|2003 Astros||8.6||2484||23||Billy Wagner||2.8||0.327|
|2003 Dodgers||10.2||1943||49||Eric Gagne||3.4||0.334|
|1990 Athletics||7.6||1704||38||Dennis Eckersley||2.8||0.366|
|1972 Athletics||5.9||1498||30||Rollie Fingers||2.8||0.475|
|2003 Angels||10.7||2155||45||Brendan Donnelly||2.7||0.252|
|2010 Giants||7.0||2029||23||Brian Wilson||2.3||0.329|
|1987 Blue Jays||9.4||2137||37||Mark Eichhorn||2.7||0.286|
|2013 Braves||9.0||1942||40||Craig Kimbrel||2.8||0.312|
|1995 Indians||8.2||1818||38||Jose Mesa||1.9||0.233|
|1998 Rockies||8.1||1950||33||Dave Veres||2.1||0.260|
|1984 Tigers||8.8||2068||35||Willie Hernandez||3.6||0.407|
|2006 Twins||9.8||2115||40||Joe Nathan||2.8||0.286|
|2010 Padres||8.6||2115||32||Heath Bell||2.3||0.267|
|2001 Mariners||7.9||1951||32||Arthur Rhodes||2.3||0.290|
|2004 Cardinals||7.7||1891||32||Jason Isringhausen||1.9||0.247|
|1979 Rangers||8.2||1765||40||Jim Kern||4.0||0.490|
|1994 Expos||5.8||1568||27||John Wetteland||1.9||0.325|
In almost all cases the best reliever by SPAR is also the best by RVL. Mark Eichhorn of the 1987 Toronto Blue Jays breaks this rule. Tom Henke tossed the highest RVL for the Jays that year but threw many fewer innings.
The Baltimore Orioles and Philadelphia Phillies enjoyed great bullpens in the 1970s but also starting rotations that did so much work the releivers spent little time in the game. Those teams' bullpens thus contributed less SPAR than the relief squads listed.
The 1994 Montreal Expos squeezed out 5.8 SPAR in 114 games. Extrapolating that linearly over 162 games gives 8.3 SPAR.
The 1979 Texas Rangers are an interesting team that was as much off my radar as possible until I looked at them. Aside from a great bullpen the everyday cast featured several noteworthy players, including Oscar Gamble, Al Oliver, Buddy Bell, Mickey Rivers, and the immortal John Grubb. The bullpen was almost all Jim Kern, who threw 143 innings in 71 appearances. Sparky Lyle threw some quality innings too. 1979 was the middle year of a five-season stretch of consecutive winning years for the Rangers, the team's first stretch of success.
There was much good relief in the Los Angeles area in 2003, notably for the Angels the season after their World Series win and a year following Troy Percival's last great season.