The Mendoza Lines

In my last post I listed Luis Mendoza as a longshot to make the rotation, and I believe that's certainly true. His two late season starts - in which he allowed just 2 earned runs in 14.2 innings - has some people convinced there's something there. Spoiler alert, there's not. His 4.3 SO/9 and 3.1 BB/9 in those two starts were pretty much identical to the rest of his career (4.6 SO/9 and 3.5 BB/9), those are numbers that are not exactly conducive to sustained success.

Since 2000 there have been 21 seasons in which a starting pitcher had a 4.5 or lower SO/9 and a 3.0 or higher BB/9 (minimum 162 IP). Of those, only three managed an ERA+ of 100 or higher - Kirk Rueter (108) and Dustin Hermanson (101) in 2000, and Jason Marquis (103) in 2005.

Here's the entire list, notice the two Royals and ask yourself if you want to witness a season like those again.

Rk	Player	ERA+	SO/9	BB/9	IP	Year	Tm
1	Kirk Rueter	108	3.47	3.03	184.0	2000	SFG
2	Jason Marquis	103	4.35	3.00	207.0	2005	STL
3	Dustin Hermanson	101	4.27	3.41	198.0	2000	MON
4	Darren Oliver	99	4.39	3.04	180.1	2003	COL
5	Livan Hernandez	96	3.96	3.48	204.1	2007	ARI
6	Pat Rapp	95	4.34	3.76	170.0	2001	ANA
7	Tom Glavine	93	4.03	3.24	183.1	2003	NYM
8	Scott Schoeneweis	93	4.13	3.55	170.0	2000	ANA
9	Josh Fogg	93	4.14	3.33	178.1	2004	PIT
10	Kirk Rueter	92	2.65	3.12	190.1	2004	SFG
11	Kirk Rueter	91	3.82	3.04	195.1	2001	SFG
12	Jimmy Anderson	90	3.88	3.62	206.1	2001	PIT
13	Steve Trachsel	88	4.32	4.26	164.2	2006	NYM
14	Jimmy Haynes	85	3.97	4.52	199.1	2000	MIL
15	Damian Moss	83	4.29	5.00	165.2	2003	TOT
16	Mark Redman	82	4.10	3.40	167.0	2006	KCR
17	Kenny Rogers	79	4.25	3.68	173.2	2008	DET
18	Mike Hampton	78	3.73	4.58	178.2	2002	COL
19	Brad Penny	77	3.67	3.07	181.2	2011	DET
20	Jason Marquis	74	4.45	3.47	194.1	2006	STL
21	Jose Lima	63	4.27	3.25	168.2	2005	KCR

Provided by Baseball-Reference.com: View Play Index Tool Used

A couple good starts is one thing, doing it over the course of a full season is far more challenging.