Beware, American League. In addition to their stellar pitching, hitting and solid defense, the A's are now starting to hit for power.
Winners of 31 of 42 games, Giants fans also have little to complain about.
The two hottest teams in baseball are neighbors in the Bay Area, but it's too soon to crown them the best teams in baseball. Or is it?
In the National League, the Brewers have returned to former form, and the Nationals are streaking. But don't forget about the Marlins and the Cardinals.
Fans who root for the Blue Jays, Angels and Tigers should also feel good about their postseason chances.
Remember, the Tigers have eliminated the A's from postseason play in each of the last two seasons, and we're a long way from October.
For the fourth consecutive season, MLB.com has set up a panel of experts to vote on the top 15 teams each week. The group includes MLB.com vice president and executive editor Carlton Thompson, executive editor Matthew Leach, columnists Mike Bauman, Hal Bodley, Anthony Castrovince, Richard Justice, Tracy Ringolsby, Phil Rogers and Lyle Spencer along with reporters Alyson Footer and Jesse Sanchez.
What do you think? Agree, disagree? Have your opinion counted by submitting your own Power Rankings.
1. Athletics: Oakland boasts a Major League-leading plus-128 run differential, leads baseball with 274 walks and has now hit a home run in season-high 16 consecutive games. The A's lead the Angels by 4 1/2 games in the AL West standings.
Last week: 1
2. Giants: It's a good time to be a Giants fan. San Francisco has the Majors' best record (42-21) and is on pace for 108 wins, which would top the previous franchise record of 103, set in 1962 and '93. No team has won a higher percentage of its home games than the Giants have at AT&T Park, and 17 of their next 22 games will be played in San Francisco.
Last week: 2
3. Blue Jays: Toronto experienced how quickly things can turn over the weekend. The AL East leaders were shut out Saturday and Sunday by the Cardinals, leading to their first series loss since dropping one against the Angels in early May.
Last week: 3
4. Brewers: Milwaukee has found its early-season form. With their 10th victory in 16 games on Sunday against the Pirates, the NL Central-leading Brewers entered Monday's off-day 12 games over .500, back to within one win of their high mark of the season. Yovani Gallardo and Francisco Rodriguez are both having campaigns to remember.
Last week: 4
5. Angels: The Halos have won three in a row and will look to gain ground in the AL West when they square off against the first-place A's in series that starts Monday. Josh Hamilton is in a groove at the plate, going 8-for-23 since getting activated off the disabled list.
Last week: 7
6. Tigers: The AL Central leaders took two of three against Boston over the weekend, but they're still searching for answers in their inconsistent bullpen. Detroit has given up 44 runs in the ninth inning, and the 10 homers allowed in the ninth are tied for the most in baseball. The 4.77 ERA by Tigers relievers ranks last in the Major Leagues.
Last week: 5
7. Nationals: Washington appears to be heating up heading into this week's showdown with San Francisco. The Nats have won five of six and are 7-3 in their last 10. Only the Giants (8-2) have been better in the NL in their last 10.
Last week: 15
8. Mariners: Seattle ace Felix Hernandez is off to one of the best starts of his career, and that's part of the reason the Mariners remain in the hunt in the AL West. King Felix fanned a career-high 15 against the Rays on Sunday, moving to 8-1 with 2.39 ERA over 14 starts.
Last week: 11
9. Marlins: Miami is 3-2 on the current road trip, which continues on Tuesday at Texas, and the club is starting to play better away from home. The Marlins are still 11-19 on the road, but they've won eight of their last 12 away games and are in a virtual tie for the top spot in the NL East standings.
Last week: 13
10. Cardinals: They got off to a slow start this season and trail the first-place Brewers by five games in the NL Central standings. The good news? St. Louis is coming off back-to-back wins. The not-so-good news? The streak comes after losing nine of 12 games.
Last week: 8
11. Dodgers: The offense has been scuffling lately, and manager Don Mattingly has gone public with his frustrations. The club has lost six of its last 10 games and has been plagued by the injury bug. Carl Crawford, Juan Uribe and A.J. Ellis are all on the disabled list, while Yasiel Puig and Dee Gordon are battling minor hip injuries.
Last week: 9
12. Braves: Atlanta has lost four of five, including two of three to the D-backs in Phoenix over the weekend. A bright spot duing the struggles: Evan Gattis has gone 13-of-33 with four home runs, 10 RBIs and four runs scored during his current nine-game hitting streak.
Last week: 6
13. Indians: The Tribe is surging, moving a game above the break-even mark for the first time since April 9 with a victory against the Rangers on Sunday. The victory was the eighth in the past nine games and the 13th in the past 19 for the Indians, who now reside in second place in the AL Central.
Last week: NR
14. Orioles: Nelson Cruz is proving to be the bargain of the offseason. The outfielder continues to pace Baltimore's offense with 21 home runs and 55 RBIs through Sunday. The O's lost two of three to the A's over the weekend and trail the first-place Blue Jays by 5 1/2 games in the AL East.
Last week: 14
15. Royals: Kansas City has won seven of 11 and sits in the middle of the standings in the AL Central. It's a good time to be on a winning streak. After Monday night's finale against the Yankees, the Royals resume play against the AL Central for the next nine games against Cleveland, Chicago and Detroit.
Last week: NR