Sunday open thread: Athletics tiebreakers and magic numbers

The Magic Number formula is well-known: Take the number of games in a season (162), add one, subtract your own team's wins, and subtract your opponent's defeats. The result is the number of your wins and opponent losses needed to eliminate your opponent from contention. For the Athletics, 76 wins goes a long way.

To win the AL West: 35

	OAK wins	Opp. Losses	Magic Number
LAA	76	52	35
SEA	76	58	29
HOU	76	75	12
TEX	76	79	8

Yes, the Texas Rangers are mathematically still in the race for the AL West.

Two-team tiebreaker

Any tie atop the West must be broken by an additional game, because the loser is either forced back into the one-game Wild Card Game or out of the postseason entirely. In the AL West, every team plays every other team 19 times, so the first to ten resolves who has home field in a two-team tie for the AL West.

• Oakland vs. Los Angeles Angels: A's lead 8-3.
• Oakland vs. Seattle Mariners: Mariners lead 6-7.

Three-team tiebreaker

In case of a three-way tie for the AL West, we first have to ask if any club has won both season series against the other two (left column first, then top row):

	OAK	LAA	SEA
OAK		8-3	6-7
LAA	3-8		5-7
SEA	7-6	7-5

If the season ended today, the Mariners would have the first choice in choosing their designation in a three-team tiebreaker because they have better records against both the A's and Angels, followed by the A's with a better record than the Angels. What becomes of these teams depends on whether there are two, one, or no Wild Card spots available for the AL West teams.

Two games would be played. First, Team A would host Team B on Monday, September 29. If there are two Wild Card spots, the loser of that game is one of the Wild Cards. If there one or zero Wild Ward spots, the loser of that game does not make the postseason.

Second, the winner of the first game hosts Team C on Tuesday, September 30. If there is a Wild Card spot, the loser of that game is one of the Wild Cards. If there is no Wild Card, the loser does not make the postseason.

What if the Angels go 5-2 or better against Seattle the rest of the way, such that no team has a better record against the other two?

In that scenario, we take the combined winning percentages amongst the other clubs combined, with the team with the highest winning percentage getting to choose their designation first, followed by the team with the next highest winning percentage. As of right now, that table looks like:

	Win	Loss	GB	M#
OAK	14	10	--
SEA	14	11	0.5	13
LAA	8	15	5.5	9

Four-team tiebreaker involving a fourth team outside the division

The most likely scenario for a three-team tie atop the AL West involves the A's and Angels beating each other up and the Mariners gaining ground in the intra-division games. There's no reason a fourth team like the Tigers, Royals, or Yankees can't tag along. The designations for Teams A, B, and C would first be determined using the three-team tiebreaker as above between the three AL West clubs. Team D will always be the team outside the division.

Two Wild Card spots

Three or four tiebreaker games would be played over two days.

First, on Monday, September 29, Team A would host Team B, and Team C would host Team D.

Scenario 1: If Team D wins, Team D is a Wild Card. The winner of the Monday game between Team A and Team B is the AL West champion. The loser of the A/B game hosts Team C on Tuesday, September 30. The winner of the Tuesday game is the other Wild Card and the loser does not make the postseason.

Scenario 2: If Team C wins, the winner of the game between Team A and Team B hosts Team C on Tuesday, September 30. The winner of that game is the Division Champion, and the loser is one Wild Card. The loser of the A/B game would host Team D on Tuesday, September 30 to determine the other Wild Card.

One Wild Card spot

Two or three tiebreaker games would be played over one or two days.

First, on Monday, September 29, Team A would host Team B, and Team C would host Team D.

Scenario 1: If Team D wins, Team D is the Wild Card and Team C does not make the postseason. The winner of the game between Team A and Team B is the AL West Champion, and the loser does not make the postseason.

Scenario 2: If Team C wins, then the winner of the game between Team A and Team B hosts Team C on Tuesday, September 30. Team D and the loser of Team A and Team B were eliminated Monday. The Tuesday game determines who is the AL West Champion and who wins the AL Wild Card berth.

Five-team tiebreaker involving two teams outside the division

Search your religious text of choice for the tiebreaker sequence.

To reach the postseason: 28

	OAK wins	Opp. Losses	Magic Number	Notes
SEA	76	58	29	M# for home field in the AL Wild Card
DET	76	59	28	M# for the second Wild Card
NYY	76	61	26
TOR	76	63	24
CLE	76	63	24
TB	76	66	21
CWS	76	70	17
MIN	76	71	16
BOS	76	73	14
HOU	76	75	12
TEX	76	79	8

Assuming everybody has a .500 record, postseason clinching day could come around September 22. Sooner if the A's start pulling away as they did in 2013. The last home game for the A's is September 24.

To clinch home field in the ALCS: 33, in the ALDS: 31

	OAK wins	Opp. Losses	Magic Number
BAL	76	54	33
KC	76	56	31

Games to watch

What else were you going to do today besides figure out tiebreakers and magic numbers? The team in bold is the team to watch:

Time (PT)				Notes
10:35 AM	Mariners	at	Red Sox	Home Field AL Wild Card M# = 29
11:10 AM	Tigers	at	Twins	Postseason M# = 28
11:20 AM	Orioles	at	Cubs	ALCS Home Field M# = 33
12:05 PM	Royals	at	Rangers	ALDS Home Field M# = 31
5:05 PM	Angels	at	Athletics	AL West M# = 35

Have a good baseball day.