The Cubs have sat atop the National League standings for much of the season, and on Friday that status became official.
After Chicago's 5-0 victory over St. Louis in the afternoon at Wrigley Field, Washington's' 6-5, 11-inning loss at Pittsburgh that night guaranteed the Cubs home-field advantage in both the NL Division Series and NL Championship Series. The best the Nationals can do now is finish the regular season tied with the Cubs at 98-64, but Chicago owns the tiebreaker thanks to winning the season series, 5-2.
There's nothing the Cubs can do about the World Series, if they get there, because the American League locked up home-field advantage by winning the All-Star Game back in July. But the NL's top seed will open the best-of-five NLDS at Wrigley Field on Oct. 7 against the winner of the NL Wild Card Game -- almost certainly the Mets, Giants or Cardinals. Game 2 (Oct. 8) and Game 5 (Oct. 13, if necessary) also would be at the Friendly Confines, where the Cubs are 56-23.
If the Cubs advance, they would face the winner of the other NLDS, which figures to pit the Dodgers against the Nationals. In that best-of-seven contest, Games 1-2 would be at Wrigley, along with Games 6-7, if necessary.
But before the Cubs worry about Los Angeles or Washington, they will have to get past the winner of the NL Wild Card Game, which will be played Oct. 5. History says that's no guarantee, despite the advantage of facing a team that just played an extra, do-or-die game in another city.
In four years under the current playoff system, top seeds in the AL and NL have gone a combined 4-4 in Division Series against Wild Card Game winners. That includes the Cardinals' loss to the Cubs last year. On the other hand, two top seeds (2013 Red Sox, '15 Royals) have won championships during that time.
Over the final week of the regular season, the Cubs can sit back and see how the NL Wild Card race develops. Currently, the Mets and Giants are slated to square off, with the Cardinals close behind.
Here is a look at each of those potential matchups and how they would set up for the Cubs.
METS
82-72 (+26 run differential)
The Mets won the season series, 5-2, including a four-game sweep at Citi Field from June 30-July 3, during the Cubs' toughest stretch of the season. Of course, the Cubs won the 2015 season series, 7-0, before the Mets swept them in the NLCS, which shows how little those head-to-head results can mean.
"Their pitching was unbelievably good," Cubs manager Joe Maddon said of the 2015 Mets. "When you run into hot pitching, there's not much you can do about it."
But this year's Mets wouldn't have Matt Harvey or Jacob deGrom in a potential NLDS matchup, as the club has been hit hard by injuries. That likely leaves Noah Syndergaard (who is skipping Saturday's start due to strep throat), ageless wonder Bartolo Colon and midseason callups Seth Lugo and Robert Gsellman in the rotation for the postseason.
The key for the Cubs would be keeping the Mets in the ballpark. New York gets more of its runs from homers than any other team and is just 10-33 when it doesn't go deep at least once. Fortunately for Chicago, its staff has MLB's seventh-lowest home run rate, and Jake Arrieta, Kyle Hendricks and Jon Lester all rank in the top 20 individually in that category.
GIANTS
81-73 (+55 run differential)
The Cubs have taken four of seven from San Francisco but have faced two very different clubs. They dropped two of three at AT&T Park in May, during a first half the Giants finished 57-33, three games ahead of the Cubs. But Chicago took three of four at Wrigley to open September, part of the Giants' NL-worst 24-40 run after the All-Star break, which has featured offensive struggles and bullpen woes aplenty.
What the Giants have going for them if they survive their second-half swoon is a rotation with a formidable top two, in Johnny Cueto, and 2014 NLCS and World Series MVP Madison Bumgarner. For that matter, former Cub Jeff Samardzija has a 2.40 ERA over his past nine starts.
While the Giants have one of MLB's lowest homer totals, in stark contrast to the Mets and Cardinals, they also have MLB's second-lowest strikeout rate and third-highest contact rate. That approach has served them well in October in recent even years.
CARDINALS
80-73 (+55 run differential)
The Cubs' win Friday, in the opener of a three-game set, gave them a 9-8 edge in the season series. Chicago has had more success at Busch Stadium, going 6-3, and of course beat the Cardinals in four games in last year's NLDS.
The biggest issue for the Cardinals is probably their rotation. Of the six pitchers who have made more than three starts for the club this season, only Carlos Martínez has an ERA below 4.45 in that role.
On one hand, St. Louis poses a challenge for opposing pitchers, ranking fourth in MLB in weighted runs created-plus (wRC+), just behind the Cubs. On the other hand, the Cards have been prone to mistakes, ranking 28th in FanGraphs' overall baserunning metric, third in most errors committed and 25th in Ultimate Zone Rating.