2015 MLB Relative Power Index (RPI),as of the games of June 5,2015 from ESPN.GO.COM

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	St. Louis Cardinals	.543	37	18	.673	.500	1	226	156	37-18	.677
2	Kansas City Royals	.533	30	22	.577	.518	3	231	189	31-21	.599
3	Minnesota Twins	.521	32	22	.593	.497	7	243	225	29-25	.538
4	Houston Astros	.520	34	22	.607	.491	4	237	213	31-25	.553
5	Detroit Tigers	.518	28	28	.500	.524	8	226	237	27-29	.476
6	Los Angeles Dodgers	.517	31	24	.564	.501	5	246	197	34-21	.609
7	Chicago Cubs	.514	28	25	.528	.510	10	212	218	26-27	.486
8	New York Yankees	.513	30	25	.545	.503	12	251	231	30-25	.541
9	San Diego Padres	.512	28	28	.500	.516	18	245	247	28-28	.496
10	Pittsburgh Pirates	.511	30	24	.556	.496	9	234	191	32-22	.600
11	Cleveland Indians	.509	26	28	.481	.519	19	237	233	27-27	.509
12	San Francisco Giants	.507	31	25	.554	.492	2	228	222	29-27	.513
13	Texas Rangers	.505	29	26	.527	.498	16	256	246	29-26	.520
14	Los Angeles Angels	.504	28	27	.509	.502	13	221	216	28-27	.511
15	Tampa Bay Rays	.500	30	26	.536	.488	14	210	193	30-26	.542
16	New York Mets	.500	30	26	.536	.488	11	212	209	28-28	.507
17	Washington Nationals	.499	30	25	.545	.483	6	241	234	28-27	.515
18	Arizona Diamondbacks	.498	26	28	.481	.504	20	259	250	28-26	.518
19	Chicago White Sox	.497	25	28	.472	.505	24	195	243	21-32	.392
20	Toronto Blue Jays	.493	26	30	.464	.502	21	289	250	32-24	.572
21	Baltimore Orioles	.490	25	29	.463	.499	17	222	226	27-27	.491
22	Seattle Mariners	.489	24	31	.436	.506	15	193	222	24-31	.430
23	Oakland Athletics	.485	23	34	.404	.513	27	242	234	29-28	.517
24	Cincinnati Reds	.484	23	30	.434	.500	25	207	236	23-30	.435
25	Colorado Rockies	.482	24	29	.453	.492	26	234	270	23-30	.429
26	Boston Red Sox	.481	25	31	.446	.493	23	210	258	22-34	.399
27	Atlanta Braves	.476	26	28	.481	.475	22	232	242	26-28	.479
28	Miami Marlins	.472	23	32	.418	.490	28	213	227	26-29	.468
29	Milwaukee Brewers	.472	19	36	.345	.514	30	208	271	20-35	.371
30	Philadelphia Phillies	.459	21	35	.375	.486	29	175	249	19-37	.331

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.