More pushback against thoughts of NL superiority.
Playoff teams if the playoffs began today:
AL East: Blue Jays 69-52 (.570) +7 ALE, +1 ALC, +3 ALW, +6 NL. The Jays are solid across the board, with winning records in all divisions. They've played their two main competitors, the Red Sox and Orioles, to the plus side of even (7-6 against both) and feasted a bit on the Yankees (9-3). The only team that has given them trouble is the White Sox (1-5), and they're just 6-7 against the Rays.
AL Central: Francona-men 69-50 (.580) +16 ALC, -5 ALE, +5 ALW, +3 NL. Cleveland owes almost all of its winning record to its unlikely dominance over its division: 9-3 vs ChiSox, 11-1(!!!) vs Tigers, 8-5 vs KC. That's a total of +19, or Cleveland's overall plus wins. Oddly, the Indians have a losing record against the weakest ALC team, the Twins, at 5-8. The Indians have also made hay against AL bottom feeders the Angels (6-1) and the Rays (5-1). Against top AL teams, Cleveland doesn't look so hot, with losing records against the O's (1-5), Red Sox (2-4), Mariners (3-4) and Rangers (1-2), while playing the Jays even (2-2).
AL West: Rangers 72-50 (.590) +13 ALW, +1 ALE, +3 ALC, +5 NL. The Rangers, with a run differential of +7 (570 RS vs 563 RA) are the unlikeliest of playoff contenders. But they've reached their peak the hard way, going 27-8 in 1-run games. The key for the Rangers has been kneecapping their closest rivals: they're 11-2 against the Astros and 8-4 against the Mariners, while going a collective .500 against the weaker Angels and A's (13-13 total). They have also dominated the Royals (6-1), while having trouble with the Twins (2-5). They're .500 against the big three in the AL East (Bal 4-3, Bos 3-3, Tor 3-4), and looking good against the AL Central (Cle 2-1, Det 4-2).
WC1: Orioles 67-53 (.558) +5 ALE, +13 ALC, -7 ALW, +3 NL. The O's are a collective -1 against the other top 3 teams of the AL East, earning their +5 in the division on the strength of a 9-3 record against the struggling Rays. Their dominance of the AL Central is thorough, with single losses in their season series to-date to the Indians, Tigers and Twins (13-3 total) and winning records against all five teams. Houston (1-3) and Seattle (1-6) have given the O's the most trouble, with the Rangers also taking the season series (3-4), leading to that -7 mark against the AL West.
WC2: Red Sox 67-53 (.558) +2 ALE, -3 ALC, +8 ALW, +7 NL. The Red Sox have played the AL East about even, with their 6-7 record against the Blue Jays the only negative. The Tigers have presented their greatest challenge, with the end-of-July reverse sweep at Fenway anchoring the current 0-4 record. About half of their overall +14 record is due to dominance over the AL West, with the Astros (5-2) and A's (3-0) proving beatable. The other half of the Sox' overall positive record is due to continued dominance over NL teams (12-5), with only the Dodgers eking out a series win in the spacious confines of Dodger Stadium.
NL East: Nationals 71-49 (.592) +18 NLE, 0 NLC, -2 NLW, +6 AL. The Nationals would be nothing without their little brothers in the NL East. The have feasted on the Braves (9-1), Phillies (8-4) and Mets (9-4), leading to +17 of their overall +22 wins. The Nats also dominated the AL Central, winning series against four of the five teams and splitting four with the Indians. They've had trouble against their main NL rivals, going 2-5 against the Cubs and 1-5 against the Dodgers. Good teams win the games they're supposed to win, so with 22 games left against the bottom three of the NL East expect a bunch more Ws for the Nats, but don't expect too much from them in the playoffs.
NL Central: Cubs 77-43 (.642) +5 NLE, +18 NLC, +2 NLW, +9 AL. The Cubs have beaten just about everybody, particularly feasting on their NL Central brethren. The Reds (10-3), Brewers (9-3) and Pirates (9-3) have offered little resistance. Only the Cardinals (6-7) have provided a challenge. They rolled over the AL West, going a collective 11-2 with a September series against the Astros still to come. Who's going to stop them? They've had trouble from the Mets (2-5) and three NL West teams -- the Giants, Rockies and Padres -- have each taken 2 of 3 against the Cubs to date.
NL West: Dodgers 67-53 (.558) +7 NLE, +3 NLC, +5 NLW, -1 AL. The Dodgers have taken care of business at home, leading the season series against the three weaker NL Westers. Against the better NL teams they've been handled by the Giants (4-6), Cubs (1-3), Pirates (2-5) and Marlins (0-4), but have handled the Cardinals (4-2), Nationals (5-1) and Mets (4-3). Against the AL East, they won two of three each against the Red Sox and Blue Jays, lost two of three to the Orioles and split four with the Rays. Closer to home, the Angels handed them their lunch with a 3-1 series win.
WC1: Giants 67-54 (.554) +1 NLE, +3 NLC, +13 NLW, -4 AL. Like Cleveland, all of the Giants positive record is due to their dominance of the division. With winning records against all four division rivals, the G-men have particularly enjoyed playing the Diamondbacks (9-5) and Padres (9-3). Outside the division they look like a … well, like a .500 team, with only one season series, against the Brewers (5-1), looking lopsided. Against the top NL teams they've been … meh: Nationals 3-4, Cardinals 1-2, Cubs 2-1, Marlins (4-2), Mets 2-2, Pirates 3-4.
WC2: Cardinals 64-56 (.533) +1 NLE, +6 NLC, +4 NLW, -3 AL. Only the Pirates (5-8) in the NL Central have figured out how to stop the Cardinal, who have dominated the Brewers (9-3) and bested the Reds (7-5) and, most surprisingly, the Cubs (7-6). The Nationals (2-5), Dodgers (2-4) and Marlins (3-4) have had their number, while they've bested the Bochy-boys and Mets (2-1 each). The Cards haven't fared well against the AL, losing series to the Rangers (0-3) and Mariners (1-2), splitting a home-and-home series with Houston (2-2 - each win by the visiting team), and losing three out of four to the cross-state rival Royals. Only a mid-May sweep over the Angels (3-0) has softened an otherwise rough go against the AL.
What does all this mean? To me it means that beyond the Cubs, the top teams are pretty evenly matched, with a bit of advantage to the AL clubs based on their more difficult schedules. Jon Abbey noted above the overall win differentials for each division. Another poster discounted that notion, but I think it's valid.
ESPN posts an RPI standings which includes a strength of schedule (SOS) component. Now, due to the relatively small pool of opponents (compared to college basketball) the SOS scores don't vary too widely, but there is a difference. The range runs from the Dodgers (.490) to the Blue Jays, Royals and White Sox (.508). Among the other playoff bound teams (if the playoffs started today), the Orioles (.507), Red Sox (.506) and Rangers (.505) have high SOS scores, while the Giants (.491), Cubs (.494), Cardinals and Indians (.499) have low SOS scores.
The top of the RPI standings look like this:
Cubs .531
Rangers .526
Blue Jays .523
Orioles .520
Nationals .519
Indians .519
Red Sox .519
Mariners .511
Tigers .510
Cardinals .508
Giants .507
Dodgers .507
Or put another way, Cubs clearly in front, every AL contender even with or slightly better than the Nationals, and the bottom three NL contenders not even surpassing two AL clubs that won't make the playoffs. That seems about right to me.