There have been 12 single-game tiebreakers in MLB history. Each of them brought the nerves and anticipation of a playoff matchup, even though they were played as regular-season games -- but game No. 163 is now a thing of the past.

With an expanded playoff format launching this October, MLB decided there wasn't enough room on the calendar to break ties in that extra-game manner anymore. Instead, a set of tiebreaking rules will now decide not only seeding but also who gets into the postseason altogether if 162 games aren't enough to determine the 12-team field. This means that the series your favorite team played way back in the first half could have a huge impact on its playoff hopes.

"It's going to become a big deal when everyone (the fans) wakes up and realizes what's going on," Milwaukee Brewers manager Craig Counsell said last month.

Counsell's team could be impacted directly, as Milwaukee is currently on the outside of the last wild-card berth in the National League, chasing the San Diego Padres for that final postseason spot. But the Brewers will have to make up a little extra ground this year since they lost their season series to the Padres 4-3, meaning if the teams finish with the same record, San Diego is in and Milwaukee is out.

"We finished games against them in ... early June," Counsell said. "We were aware of it at the time, but there's 110 games left at that point. There's not much to be done.

"We knew the rule," Counsell said. "Everyone knew it ...They felt fitting a tiebreaker game into the schedule wasn't feasible."

The league understands some of the angst that could exist if a team is eliminated by a season series played around Memorial Day but says the trade-off of more teams in the mix for a playoff spot is worth it.

"We are excited that more of our fans will get to experience postseason baseball this year as part of the expanded playoff format," Morgan Sword, executive vice president of baseball operations, said. "Due to the increased number of postseason games, we had to ensure that the regular season would end on time."

Though the postseason format is spelled out in the recently signed collective bargaining agreement, there is discretion when it comes to the specifics of the tiebreaker rules that will allow the league to examine the impact and make changes if needed. As players and teams realize the stakes, the new rules could also lead to a further emphasis on head-to-head matchups.