Some notes on individual players on each one of these teams:
The obvious here is that the Nationals are ready to take the NL East now! Their team FIP, 2.27 is by far, the best in the MLB. (Gio Gonzalez: 1.51 in 23 IP, Stephen Strasburg: 1.74 in 25 IP). Gio is yielding a low 0.228 BABIP.
2nd in the AL in FIP at 3.39 they also seem lucky so far with a 0.256 BABIP. Going into Thursday evening, Phillip Humber has a FIP of 1.30 in 14 IP and Jake Peavy, who apparently took a trip in the Delorean, has a 2.07 FIP in 28 IP. Their team WHIP of 1.05 is 1st in the AL, but they may come back to earth soon.
Continuing on their pattern of great young pitching, there's a youngin' and an old timer dominating in WHIP (Tommy Milone: 0.85 WHIP in 27 IP and Bartolo Colon: 0.93 WHIP in 34 IP. In the AL, they're 3rd in the AL in both BABIP (0.260) and WHIP (1.17).
Of course Clayton Kershaw remains the Dodgers badass (1.03 WHIP, 1.74 FIP in 22 IP), but Ted Lilly has been a solid piece of their rotation (0.85 WHIP, 3.15 FIP in 20 IP). Chad Billingsley has been pretty amazing too with a 0.93 WHIP in 23 IP.
Jason Hammel so far, proves to have been a good acquisition with a 1.00 WHIP and 2.40 FIP in 26 IP. Jake Arrieta has been a bright spot as well with 1.09 WHIP and 3.23 FIP in 24 IP.
Is Johan Santana back? A 1.22 WHIP and 1.57 FIP in 18 IP sure looks good.
A note on team wRC+. aside from the Yankees and Rangers, most of the teams mentioned are around league average, which leads me to believe that this wasn't the best to measure team offense. The Nationals are on the lower end of the list with a 85 wRC+ (10th in NL) and A's with a 65 wRC+ (14th in AL), so it's safe to say, especially with the A's, that their pitching is keeping them in games.