MLB Playoffs 2018: Explaining Wild-Card Format, Divisional Series and More

The 2018 MLB season will stretch into a Game 163 for four teams, as the NL Central and NL West division titles are still undecided after Sunday's action.

While the Chicago Cubs, Milwaukee Brewers, Los Angeles Dodgers and Colorado Rockies will all take the field on Monday and look to avoid having to play in the NL Wild Card Game, it's not too early to start looking ahead to Tuesday when the postseason begins in earnest.

What follows is a breakdown of everything you need to know about how the Wild Card Game and Division Series rounds are formatted.

Wild-Card Format

Five teams from each league qualify for the postseason—the three division winners and then the two teams with the best records who failed to win their division.

The division winners automatically advance to the Division Series, where they are joined by the victor of a one-game playoff between the two wild-card teams that essentially serves as a play-in game.

The winners of each Wild Card Game match up with the team that had the best record in their league, so the AL winner will take on the Boston Red Sox, while the NL winner will play whoever winds up winning the NL Central.

While we're still waiting on the NL side of things to be sorted out, the American League matchup for the Wild Card Game is already set. The New York Yankees (100-62) will host the Oakland Athletics (97-65) on Wednesday night.

Reliever Lou Trivino served as the "opener" for Mike Fiers on Friday, and that's how Oakland could start the Wild Card Game.

Thearon W. Henderson/Getty Images

"We're not ruling anything out," manager Bob Melvin told reporters when asked if Fiers could follow an "opener" in the Wild Card game. "I'm not saying that’s the route we're going, but we want to make sure to look at every potential avenue."

Liam Hendriks has also started eight games this season in the "opener" role and would be a candidate to pitch the first inning ahead of Fiers.

Meanwhile, Yankees manager Aaron Boone still needs to choose from the trio of J.A. Happ, Masahiro Tanaka and Luis Severino for his starter in the winner-take-all game.

"We had a lot of men on it last night," Boone told reporters of the starter decision. [GM Brian Cashman] and the coaching staff and the support staff really dove into it. We're closer to that decision. I don't have it for you today, but in my mind, I'm getting a lot closer to which way I want to go."

As we've already mentioned, the National League side is still up in the air. All we know right now is that the losers of Monday's games will meet on Tuesday in the Wild Card Game.

Division-Series Format

The Divison Series is played under a best-of-five format, with the higher-seeded team hosting Games 1, 2 and 5, if necessary.

With two travel days sprinkled into the five-game series, teams often face tough decisions on whether to go with a No. 4 starter or bring back an ace on short rest.

In the AL, the Boston Red Sox (108-54) will host the Wild Card Game winner, and the Houston Astros (103-59) will host the Cleveland Indians (91-71).

Again, things are still cloudy on the NL side.

The NL Central division champ will host the Wild Card Game winner, while the NL West champ will host the Atlanta Braves (90-72) which are the only team to have locked down a division title to this point.

We've seen time and again that once you punch your ticket to the postseason, anything can happen in October.

The Red Sox and Astros look like the heavy favorites at the onset, but the same was said of the Indians last season, and they failed to advance beyond the Division Series.

One thing is for sure: There's plenty more excitement to be had before the 2018 season comes to a close.