2015 MLB Relative Power Index (RPI),as of the games of April 22,2015 from ESPN.GO.COM

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	New York Mets	.579	12	3	.800	.506	6	67	44	10-5	.699
2	San Diego Padres	.568	10	6	.625	.549	7	84	61	10-6	.655
3	St. Louis Cardinals	.564	9	4	.692	.521	5	51	31	9-4	.730
4	Chicago Cubs	.561	8	6	.571	.557	14	62	57	8-6	.542
5	Los Angeles Dodgers	.559	9	5	.643	.531	3	67	55	8-6	.597
6	Detroit Tigers	.553	11	4	.733	.493	1	76	54	10-5	.665
7	New York Yankees	.548	8	7	.533	.553	20	83	64	9-6	.627
8	Kansas City Royals	.546	11	4	.733	.484	2	81	49	11-4	.732
9	Atlanta Braves	.542	8	6	.571	.532	16	57	54	7-7	.527
10	Minnesota Twins	.535	6	9	.400	.580	28	48	72	5-10	.308
11	Toronto Blue Jays	.525	8	7	.533	.523	10	87	69	9-6	.614
12	Boston Red Sox	.511	9	6	.600	.481	4	76	72	8-7	.527
13	Baltimore Orioles	.504	7	8	.467	.516	9	70	77	7-8	.452
14	Arizona Diamondbacks	.504	8	7	.533	.494	22	69	61	8-7	.561
15	Cincinnati Reds	.500	8	7	.533	.489	17	61	62	7-8	.492
16	Colorado Rockies	.498	8	7	.533	.487	8	65	70	7-8	.463
17	San Francisco Giants	.488	6	10	.375	.526	26	46	66	5-11	.327
18	Chicago White Sox	.488	6	8	.429	.508	23	50	61	6-8	.402
19	Washington Nationals	.487	7	8	.467	.493	13	60	60	8-8	.500
20	Tampa Bay Rays	.482	7	8	.467	.488	21	58	69	6-9	.414
21	Oakland Athletics	.478	8	8	.500	.470	11	83	62	10-6	.642
22	Los Angeles Angels	.458	6	9	.400	.477	12	62	66	7-8	.469
23	Miami Marlins	.453	4	11	.267	.515	27	59	73	6-9	.395
24	Seattle Mariners	.451	6	9	.400	.468	18	58	77	5-10	.362
25	Houston Astros	.449	8	7	.533	.420	25	49	51	7-8	.480
26	Cleveland Indians	.445	5	9	.357	.475	19	44	58	5-9	.365
27	Philadelphia Phillies	.443	5	10	.333	.480	30	40	65	4-11	.275
28	Texas Rangers	.435	6	9	.400	.447	24	63	75	6-9	.414
29	Pittsburgh Pirates	.428	7	8	.467	.415	15	60	54	8-7	.552
30	Milwaukee Brewers	.344	2	13	.133	.415	29	42	89	3-12	.182

Glossary

• W: Wins
• L: Losses
• PCT: Winning percentage
• RPI: Relative Power Index+
• SOS: Strength of schedule

• PWR: ESPN Power Ranking
• RS: Runs scored
• RA: Runs allowed
• EXW-L: Expected W-L*
• EXWP: Expected winning percentage*

+The basic formula is 25% team winning percentage, 50% opponents' average winning percentage, and 25% opponents' opponents' average winning percentage.
*ExW-L and ExWP are derived from Bill James' Pythagorean theorem of baseball: Runs scored [squared] / (Runs scored [squared] + runs allowed [squared]). This formula was designed to relate a team's runs scored and runs allowed to its won-lost record.