2017 MLB Relative Power Index (RPI),as of the games of July 21,2017 from ESPN.GO.COM

MLB RPI Rankings
RK	TEAM	RPI	W	L	PCT	SOS	PWR	RS	RA	EXPW-L	EXPWP
1	Los Angeles Dodgers	.545	66	31	.680	.500	0	495	326	68-29	.697
2	Houston Astros	.544	64	32	.667	.503	0	566	399	64-32	.668
3	Arizona Diamondbacks	.521	56	40	.583	.501	0	487	376	60-36	.627
4	Colorado Rockies	.521	56	42	.571	.504	0	520	476	53-45	.544
5	Washington Nationals	.513	57	38	.600	.484	0	530	424	58-37	.610
6	Boston Red Sox	.511	55	43	.561	.495	0	465	396	57-41	.580
7	New York Yankees	.509	50	45	.526	.503	0	506	403	58-37	.612
8	Tampa Bay Rays	.504	51	46	.526	.497	0	451	436	50-47	.517
9	Cleveland Indians	.503	49	45	.521	.498	0	450	377	55-39	.588
10	Chicago Cubs	.503	49	46	.516	.499	0	447	427	50-45	.523
11	Los Angeles Angels	.502	47	51	.480	.510	0	397	420	46-52	.472
12	Pittsburgh Pirates	.502	49	48	.505	.501	0	415	426	47-50	.487
13	Minnesota Twins	.502	48	47	.505	.500	0	431	495	41-54	.431
14	Baltimore Orioles	.501	46	50	.479	.509	0	444	516	41-55	.425
15	Milwaukee Brewers	.500	52	47	.525	.492	0	475	440	53-46	.538
16	Kansas City Royals	.500	48	47	.505	.498	0	401	428	44-51	.467
17	Seattle Mariners	.500	48	50	.490	.503	0	463	469	48-50	.494
18	St. Louis Cardinals	.497	47	49	.490	.500	0	438	415	51-45	.527
19	Texas Rangers	.497	46	50	.479	.502	0	468	459	49-47	.510
20	Oakland Athletics	.493	43	53	.448	.508	0	416	492	40-56	.417
21	Atlanta Braves	.492	47	48	.495	.491	0	448	481	44-51	.465
22	Toronto Blue Jays	.491	44	52	.458	.502	0	399	481	39-57	.408
23	San Diego Padres	.489	42	54	.438	.506	0	362	496	33-63	.348
24	Miami Marlins	.489	43	51	.457	.499	0	431	466	43-51	.461
25	Detroit Tigers	.488	44	51	.463	.496	0	460	481	45-50	.478
26	New York Mets	.487	44	50	.468	.493	0	453	494	43-51	.457
27	Cincinnati Reds	.483	40	56	.417	.505	0	445	527	40-56	.416
28	Chicago White Sox	.475	38	55	.409	.498	0	415	461	42-51	.448
29	San Francisco Giants	.474	37	61	.378	.506	0	384	496	37-61	.375
30	Philadelphia Phillies	.464	33	61	.351	.501	0	371	450	38-56	.405

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.