MLB Playoffs format, dates and more: Everything you need to know about the postseason

September is officially here. Not only do rosters expand, but the turning of the calendar to the last month of MLB's regular season means that we're officially in the stretch run. We're oh so close to figuring out which teams will make the postseason, and eventually, which team will win the World Series.

The MLB playoff format has seen several changes over the years. We've gone from only having teams with the best records in each league participate, to having one Wild Card team, to two, and now three. Six teams from each league will eventually have the chance to participate in and win the World Series.

This article will cover everything you need to know about the MLB postseason from the updated playoff format, to key dates, to how rosters work and so much more.

MLB Playoff Format

Overview of the Current Format

Overall, 12 teams will qualify for the MLB postseason - six from each league. Each league will have its three division winners and three Wild Card teams - the teams with the best records among those who don't win the division - make the postseason.

The postseason consists of four rounds - the Wild Card Series, Division Series, League Championship Series, and World Series.

Both the AL and NL uses the same seeding format which can be seen below:

 Wild Card Series

The postseason begins with the Wild Card series. Four of the six qualifying teams in each league will participate in this series with a spot in the Division Series on the line. The top two seeds in each league receive byes, allowing them to automatically advance past the Wild Card Series.

The Wild Card Series format looks like this in both leagues:

The No. 3 and No. 4 seed in each league will host a three-game series at their home ballpark against the No. 6 seed and No. 5 seed respectively. All three games will be held at the higher seed's field, and the winner of that series moves on to the next round.

Division Series (ALDS and NLDS)

The teams that are lucky enough to advance past the Wild Card Series will play in the Division Series, either the ALDS for American League teams or the NLDS for National League teams.

This series is a best-of-five, meaning one team needs to win three games to move on to the next round. This is a step up from the two wins needed to advance past the Wild Card Series.

The top two seeds in each league will receive home-field advantage in this series, meaning three of the five games will be played at their stadium. The other two teams that advanced past the Wild Card series will have to win at least one road game to move on. The first two games and the fifth game (if necessary) will be played at the home ballpark of the higher seed.

League Championship Series (ALCS and NLCS)

After the Division Series, we'll arrive at the League Championship Series. The LCS is the last round of the postseason before the World Series. It determines which team will represent its league (one in the AL and NL) in the World Series.

This series is a best-of-seven, another step up from the Division Series. One team will need to win four of the seven games to win the Pennant and move on to the World Series.

Home Field advantage in this series will again be held by the team with the highest seed remaining in each league. The team that has home field advantage will host the first two and last two games (if necessary) of this crucial series.

Home-field advantage is important but ultimately isn't the end all be all. Last season in the ALCS we saw the road team win all seven games, leading the Texas Rangers to upset the Houston Astros on their way to an eventual World Series win.

The World Series

Once we've determined who wins each league, we'll arrive at the World Series. This is for all of the marbles. The winner of this series will be the World Champion of the season.

Like the League Championship Series, the World Series will be a best-of-seven affair, meaning that one team will have to win four of the seven to be crowned champions.

The format is exactly the same. Home-field advantage will go to the team with the best record among the two participating, and that team will get to host the first two and last two games (if necessary) of the World Series.

Key Dates for the MLB Playoffs

Timeline of the Postseason

Right when October rolls around, the MLB playoffs will officially begin. They start right on October 1 with Game 1 of the Wild Card Series, and depending on how long the World Series goes, the playoffs can roll into November.

What makes MLB different than the other major US sports is that it's played literally every single day. There are stretches during the regular season where teams don't get an off-day for two or three weeks. They don't play every single day in the postseason, but they do play very often.

Off-days are centered around travel (when the series shifts to another city) or before a new series gets under way.

Broadcast Schedule

The MLB postseason can be viewed on a variety of channels for those with cable, all depending on which round of the postseason we're in.

Those who do not have cable can tune in on a variety of streaming platforms including MLB.tv for those with active subscriptions and ESPN for the Wild Card Series.

How Playoff Rosters Work

MLB teams have 28-man active rosters for the month of September, but once the postseason begins, the active roster size goes back down to the traditional 26 players.

The rosters are locked in ahead of the first game of any given series, but teams can request permission from the Commissioner's Office to replace an injured player on the active roster. The downside for doing that, though, is that the injured player will be ineligible to return not only in the current round, but in the round after. Another thing to keep in mind is that if a pitcher is taken off the roster due to injury, he can only be replaced by another pitcher. The same can be said about a position player.

As for eligibility, any player who was on a team's 40-man roster ahead of August 31 at 11:59 p.m. ET is eligible to be on the postseason roster. Those on the 60-day IL are also eligible, if they were out for at least 60 days prior to being activated. Those acquired in September are not eligible for the postseason, which is why players like Tommy Pham were waived in August instead of September.

Usually in the postseason, while the roster size is the same, teams use four-man rotations, making bullpen depth that much more important. Teams also might prioritize speed coming off the bench, as any late-game run that can be stolen is that much more important.

Tiebreaker Rules and Scenarios

Unfortunately, MLB took away one of the best parts of the game, a potential 163rd game. In the past, teams with identical records either fighting for a division title or a Wild Card spot would play in a Game 163 to figure out which team earns a particular spot. Now, tiebreakers are broken by other factors, and there are no more Game 163s.

Tiebreakers are most often determined by head-to-head records. This is the only tiebreaker needed for a division race, as teams within the same division play an odd number of games (13 to be exact). For Wild Card positioning, though, things can get trickier, since teams jockeying for those spots don't always play an odd number of games against each other and can finish with a head-to-head tie.

The next factor is intradivision record. The team with the best record from within its own division will win the tiebreaker. Yes, this even breaks ties for teams who don't play in the same division.

The next tiebreaker scenario is inter-division record. If there's a tie in the intradivision record calculation, the league would then calculate which team has the best record against the other divisions in the same league. So if an NL East team is involved in a tie, their record against NL Central and NL West teams would be considered in this scenario.

If there is somehow still a tie after these three tiebreaker scenarios, we'd then proceed to look at the last half of interleague games. For an AL team, this would calculate the games within their final 81 games of the season against NL opponents. Their record against NL teams within their final 81 games of the season would be their record in breaking the tie here. This process goes back until there is a winner.