2015 MLB Relative Power Index (RPI),as of the games of June 29,2015 from ESPN.GO.COM

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	St. Louis Cardinals	.546	51	24	.680	.501	1	309	211	51-24	.682
2	Kansas City Royals	.529	44	29	.603	.505	2	317	264	43-30	.590
3	Chicago Cubs	.518	39	35	.527	.515	10	295	288	38-36	.512
4	New York Yankees	.516	41	36	.532	.511	9	364	343	41-36	.530
5	Houston Astros	.516	45	34	.570	.498	5	352	298	46-33	.583
6	Detroit Tigers	.512	39	36	.520	.509	14	327	330	37-38	.495
7	Los Angeles Dodgers	.511	43	35	.551	.498	6	330	268	47-31	.603
8	Toronto Blue Jays	.511	41	37	.526	.506	12	421	335	48-30	.612
9	Baltimore Orioles	.510	41	35	.539	.500	11	349	302	43-33	.572
10	Tampa Bay Rays	.510	42	36	.538	.500	7	284	274	40-38	.518
11	Los Angeles Angels	.509	40	37	.519	.505	15	300	301	38-39	.498
12	Minnesota Twins	.507	40	36	.526	.500	13	320	320	38-38	.500
13	Pittsburgh Pirates	.505	42	33	.560	.487	4	298	252	44-31	.583
14	Washington Nationals	.500	42	34	.553	.482	3	336	307	41-35	.545
15	San Francisco Giants	.499	42	35	.545	.484	8	329	305	41-36	.538
16	Texas Rangers	.499	39	38	.506	.496	17	334	330	39-38	.506
17	San Diego Padres	.497	37	41	.474	.504	21	327	359	35-43	.453
18	Cleveland Indians	.496	34	41	.453	.511	20	298	331	34-41	.448
19	Arizona Diamondbacks	.495	37	39	.487	.498	19	344	350	37-39	.491
20	Seattle Mariners	.495	34	42	.447	.511	24	255	306	31-45	.410
21	Oakland Athletics	.493	35	44	.443	.510	23	355	309	45-34	.569
22	New York Mets	.493	40	37	.519	.484	16	276	287	37-40	.480
23	Cincinnati Reds	.489	35	40	.467	.497	18	306	319	36-39	.479
24	Boston Red Sox	.489	35	43	.449	.503	27	317	360	34-44	.437
25	Chicago White Sox	.487	32	42	.432	.505	26	257	338	27-47	.366
26	Milwaukee Brewers	.482	30	48	.385	.515	29	290	367	30-48	.384
27	Atlanta Braves	.481	36	40	.474	.483	22	304	331	35-41	.458
28	Colorado Rockies	.475	33	43	.434	.489	25	345	391	33-43	.438
29	Miami Marlins	.473	31	46	.403	.496	28	280	317	34-43	.438
30	Philadelphia Phillies	.459	27	51	.346	.496	30	260	386	24-54	.312

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.