Baseball Player Won-Loss Records
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Mariano Rivera vs. Andy Pettitte

Mariano Rivera vs. Andy Pettitte: How Valuable Can a Relief Pitcher Be?



Elsewhere, I look at starting pitchers versus relief pitchers generally. In this article, I compare a specific starting pitcher versus a specific relief pitcher, to get a better sense of just how valuable a relief pitcher can be.

For my comparison, I chose almost certainly the best relief pitcher in major-league history, Mariano Rivera, and his longtime teammate, Andy Pettitte.

Mariano Rivera is widely viewed as a future Hall-of-Famer, probably on his first ballot of eligibility. Andy Pettitte is viewed, at best, as something of a marginal Hall-of-Fame candidate (even setting aside his connection to Brian McNamee), although he has his supporters.

On the other hand, the Yankees signed both Rivera and Pettitte as free agents within a week of each other in December of 2007.
Rivera made $15 million in 2008
Pettitte made $16 million.
So who was more valuable in his career: Mariano Rivera or Andy Pettitte?
My player won-lost records for Andy Pettitte and Mariano Rivera are shown in the table below.

Andy Pettitte Mariano Rivera
Season Games pWins pLosses Win Pct. pWOPA pWORL Games pWins pLosses Win Pct. pWOPA pWORL
1995
3110.69.80.5210.7
1.8
194.04.20.487-0.10.4
1996
3515.010.80.5812.4
3.8
619.73.60.7292.73.6
1997
3514.08.20.6303.1
4.4
667.33.80.6591.62.3
1998
3313.711.80.5371.2
2.6
546.41.90.7702.12.6
1999
3111.711.40.5080.4
1.6
666.62.50.7271.92.5
2000
3213.010.70.5491.4
2.6
667.54.00.6541.62.4
2001
3113.210.50.5571.7
3.0
718.84.00.6862.13.0
2002
229.55.90.6151.9
2.8
455.03.90.5630.41.1
2003
3314.611.70.5541.7
3.2
647.22.90.7112.02.7
2004
155.64.90.5330.6
1.2
749.43.60.7232.63.5
2005
3314.19.80.5912.8
3.9
717.73.30.7012.02.8
2006
3814.814.70.5010.8
2.3
637.13.40.6761.72.4
2007
3612.410.80.5351.0
2.4
676.43.90.6251.11.8
2008
3313.013.30.4930.1
1.5
647.62.60.7472.33.0
2009
3212.910.40.5551.6
2.9
666.23.10.6691.42.0
2010
218.66.20.5821.3
2.1
615.63.30.6261.01.6
2011
 
646.32.80.6921.52.2
2012
124.13.90.5100.2
0.6
90.70.30.7000.20.3
2013
3010.89.90.5220.7
1.8
647.13.80.6531.52.3
------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
CAREER RECORDS
(Regular Season)
533211.6174.70.54823.6
44.4
1,115126.660.80.67629.642.3
------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Postseason4417.114.10.5481.9
3.6
9613.03.50.7874.45.5
------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
CAREER RECORDS577228.7188.80.54825.6
48.0
1,211139.664.30.68534.047.8


If your stat of choice is pWORL and you include postseason games, Pettitte and Rivera's careers were about as close in value as two players could be, 48.0 - 47.8. But they got there in fairly different ways.

Mariano Rivera beats Andy Pettitte handily in regular-season career winning percentage, 0.676 - 0.548. But Rivera's advantage there is offset by two factors. First, Andy Pettitte amassed 198.9 more (regular-season) Player decisions than Rivera in his career, due to Pettitte having pitched 1,911 more (regular-season) innings than Rivera. Also, because relief pitchers have higher Player winning percentages, on average, than starting pitchers, Rivera's record is compared against a higher Positional Average (0.518) than Pettitte's (0.487).

Even with the higher Positional Average, however, Rivera beats Pettitte fairly easily in regular-season wins over positional average (WOPA), 29.6 to 23.6, and extends his lead in pWOPA by another 2.5 wins when the postseason is added.

Moving the comparison from average to replacement level allows Pettitte to gain all of the advantage back, with Pettitte beating Rivera in "replacement wins" (pWORL minus pWOPA) by 8.0 in the regular season and another 0.6 in the postseason.

So, how valuable can a relief pitcher be? Under current usage patterns, it would appear that perhaps an elite relief pitcher can be as valuable as a very good starting pitcher.



All articles are written so that they pull data directly from the most recent version of the Player won-lost database. Hence, any numbers cited within these articles should automatically incorporate the most recent update to Player won-lost records. In some cases, however, the accompanying text may have been written based on previous versions of Player won-lost records. I apologize if this results in non-sensical text in any cases.

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