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The 2018 MLB season is rapidly winding to a close, as we are now just six weeks from the start of the postseason.

With 16 teams still sporting a winning record and four division titles and four wild-card spots still very much up for grabs, there's still a lot left to be decided between now and the beginning of the playoffs.

For now, just remember that these rankings are fluid. Teams rise and fall based on where they were ranked the previous week. If a team keeps winning, it will keep climbing—it's as simple as that.

Here's where all 30 teams stand heading into the rest of this week's action:

Updated Rankings 1 Boston Red Sox (88-37) 2 New York Yankees (78-46) 3 Oakland Athletics (74-50) 2 4 Houston Astros (75-49) 1 5 Chicago Cubs (71-52) 1 6 Cleveland Indians (71-52) 1 7 Arizona Diamondbacks (69-56) 2 8 Colorado Rockies (68-56) 7 9 St. Louis Cardinals (68-57) 4 10 Atlanta Braves (68-55) 2 11 Los Angeles Dodgers (67-58) 1 12 Seattle Mariners (71-54) 6 13 Milwaukee Brewers (69-57) 2 14 Philadelphia Phillies (68-56) 2 15 Tampa Bay Rays (63-61) 2 16 Pittsburgh Pirates (63-62) 2 17 Los Angeles Angels (63-63) 2 18 Minnesota Twins (59-64) 4 19 Texas Rangers (56-70) 2 20 Washington Nationals (62-63) 4 21 San Francisco Giants (61-64) 3 22 New York Mets (54-69) 2 23 Cincinnati Reds (55-69) 2 24 Toronto Blue Jays (55-69) 1 25 San Diego Padres (49-78) 5 26 Chicago White Sox (46-77) 2 27 Miami Marlins (50-76) 28 Detroit Tigers (51-74) 2 29 Kansas City Royals (38-86) 30 Baltimore Orioles (37-87)

Teams That Impressed

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Here come the Colorado Rockies.

With an 8-1 record in their last nine games, they've gone from 3.5 games back in the wild-card standings to tied with Philadelphia and Milwaukee for the right to host the Wild Card Game.

Trevor Story continues to swing a hot bat with a .310/.333/.634 line in August that includes six more home runs to bring his season total to 26. On the mound, Kyle Freeland sports a 2.13 ERA in four starts this month, and he's quietly been one of the NL's best starters all season, going 11-7 with a 2.96 ERA in 25 starts.

The St. Louis Cardinals are the other team charging hard on the NL side.

With a 14-4 record and plus-43 run differential in August, they've climbed right back into the race for both a wild-card spot and the NL Central title, and series wins against the Washington Nationals and Milwaukee Brewers this past week only furthered their cause.

Young right-hander Jack Flaherty is 3-0 with a 0.95 ERA and 0.84 WHIP in three starts this month, while Jose Martinez is hitting a robust .400/.450/.527 to bring his season batting line to .308/.369/.468 overall.

That being said, no team had a better week than the Oakland Athletics.

By taking two of three against the Seattle Mariners and Houston Astros, they are just one game back in the AL West standings. And they avenged some early-season struggles against the reigning World Series champions.

This Oakland team is the real deal, and while it's going to have its hands full catching up to and holding off the Astros, it's in a great position to secure the second wild-card spot and reach the postseason for the first time since 2014.

The Cleveland Indians (5-1), Minnesota Twins (5-1) and Chicago White Sox (4-2) were the only other teams to win both of their series last week, as for one brief span, the AL Central didn't look quite so feeble. The only logical explanation is that they read this article from Zachary Rymer and were inspired.

Teams That Disappointed

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The Seattle Mariners suffered series losses to the Athletics and Los Angeles Dodgers last week, and in the process, they slipped further out of the wild-card picture.

It's essentially a two-horse race between the A's and M's for the second AL wild-card spot, which makes a head-to-head series loss that much more painful. The Mariners have been hanging on by a thread all season, as evidenced by their minus-42 run differential, and last week could be the beginning of the slide.

On the NL side, the Milwaukee Brewers continued their tumble down the rankings with a weekend series loss to the division-rival Cardinals.

That gives the Brew Crew a 6-10 record and minus-31 run differential for the month. They are 3.5 games back in the NL Central race and tied for the wild card.

The Pittsburgh Pirates (2-4), Washington Nationals (2-5) and San Francisco Giants (2-4) all saw their slim playoff hopes take a hit with losing weeks.

They now have a combined 19.6 percent chance to secure a postseason berth, according to the latest projections from FanGraphs.

MVPs of the Week

Hitter: Ronald Acuna Jr., Atlanta Braves

Stats: 13-for-28, 2 2B, 4 HR, 9 RBI, 11 R, 3 SB

It was quite the week for Braves rookie phenom Ronald Acuna.

The 20-year-old tied a franchise record by homering in five straight games but then had to exit the team's game on Wednesday when he was seemingly intentionally drilled by Miami Marlins pitcher Jose Urena with a fastball to lead off the game.

He returned the next day and showed no ill effects of the beaning with a three-hit game on Saturday, and he's been a force for the contending Braves in the second half.

As he looks to chase down Juan Soto and Dereck Rodriguez in the NL Rookie of the Year race, Acuna is hitting .366/.430/.789 with eight home runs in 79 plate appearances in August.

Pitcher: Jhoulys Chacin, Milwaukee Brewers

Stats: 2 GS, 2-0, 13.0 IP, 7 H, 0 ER, 2 BB, 13 K

Yu Darvish (6/$126M), Jake Arrieta (3/$75M), Alex Cobb (4/$57M), Tyler Chatwood (3/$38M), Mike Minor (3/$28M), Andrew Cashner (2/$16M) and Jason Vargas (2/$16M) all earned more money in free agency than Jhoulys Chacin, who signed a two-year, $15.5 million deal to join the Brewers.

Yet, Chacin has been as good or better than all of them:

Darvish: 8 GS, 1-3, 4.95 ERA, 1.43 WHIP

Arrieta: 24 GS, 9-8, 3.25 ERA, 1.21 WHIP

Cobb: 23 GS, 4-15, 5.09 ERA, 1.43 WHIP

Chatwood: 20 GS, 4-6, 5.22 ERA, 1.81 WHIP

Minor: 22 GS, 9-6, 4.61 ERA, 1.16 WHIP

Cashner: 23 GS, 4-10, 4.71 ERA, 1.49 WHIP

Vargas: 13 GS, 2-8, 8.10 ERA, 1.78 WHIP

Chacin: 27 GS, 13-4, 3.58 ERA, 1.17 WHIP

Finding a frontline starter looked like the biggest need for the Brewers when the offseason began, and failing to land any of the marquee names on the open market seemed like a missed opportunity at the time.

Now, after two excellent starts last week of six and seven scoreless innings, it's clear the front office made the right decision.

Video Highlights of the Week

Longest Home Run: C.J. Cron, Tampa Bay Rays (464 feet)

Despite his defensive shortcomings (-2 DRS) and limited on-base skills (.317 OBP, 6.2 BB%), C.J. Cron has been a consistent source of power for the Rays this season.

After three straight seasons with 16 home runs, he's already set a career high with 24 long balls this season while posting a 118 wRC+ and driving in a team-high 59 runs.

The 28-year-old was acquired in February in a trade with the Angels, and with team control through the 2020 season, he's proved to be a cheap middle-of-the-order solution after the front office traded away Evan Longoria, Steven Souza Jr. and Corey Dickerson during the offseason and opted against re-signing Logan Morrison.

His 464-foot blast off Red Sox starter David Price was the longest homer of the season by a Rays hitter this season, and he took on the Green Monster and emerged victorious.

Best Defensive Play: Harrison Bader, St. Louis Cardinals

Harrison Bader has been a stud in the outfield this season.

The 24-year-old rookie has been worth 3.9 WAR, and while he's been solid at the plate with a .285/.354/.453 line that includes 23 extra-base hits and 12 stolen bases, it's his defense that is making him a star.

This catch is the perfect example of his excellent mix of speed and instincts, as he turned what looked to be a sure double in the gap into a highlight-reel catch.

Bader has racked up an impressive 21 DRS with a 19.5 UZR/150 on the season, and while he's been splitting time in center field for much of the year, a Gold Glove Award could be in his future.

Must-See Upcoming Matchup

Cleveland Indians vs. Boston Red Sox (Monday-Thursday)

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The Indians have been streaking of late with a 17-6 record in their last 23 games.

However, that run of success has come against a string of non-contenders, and the uber-weak AL Central has not provided much of a test for the Tribe all season.

A big test awaits this week, though.

The Indians will head to Boston to take on the first-place Red Sox for a four-game series, the first time this season the two teams have squared off.

And while they'll miss ace Chris Sale—who is on the disabled list with shoulder inflammation—it will still be a good gauge of where the Indians are as they go up against baseball's best team.

For the Red Sox, it's a chance to further solidify their standing as the No. 1 team, and it could wind up being an ALCS preview.

All stats courtesy of Baseball Reference and FanGraphs unless otherwise noted.