Seattle Mariners Play Key Role in AL West Standings
Way back in March, the Seattle Mariners opened the season against the Oakland A’s with two games in Japan. This series allowed American and Japanese baseball legend Ichiro Suzuki to play his final two major league games in front of Japanese fans in Tokyo. The Mariners won both games, the second one 5-4 in 12 innings. All was good in the land of the latte.
Those wins were an exciting start to an impressive early-season run by the Mariners.
After the two-game series with Oakland, the wins just kept on coming. The Mariners won three of four against the Boston Red Sox, two straight over the Angels, and two of three against the White Sox. After a four-game sweep of the Kansas City Royals on the road, the Mariners were 13-2 and four games up in the AL West as they began a homestand on April 12.
Enter the Houston Astros and a dose of biting reality for the Mariners. The Astros swept the M’s, with Justin Verlander and Gerrit Cole picking up wins. Then the Cleveland Indians came to town with brooms of their own for a three-game sweep. Trevor Bauer, Shane Bieber, and Carlos Carrasco shut down what had been a hot Mariners offense during their 13-2 run.
That was the beginning of the end for the Mariners.
Since their 13-2 start, they’ve gone 50-86 and now have the fifth-worst record in the American League, at 63-88 (.417, -131 run-differential). They’re not historically bad, like the Detroit Tigers (45-105, .300, -298 run-differential) or Baltimore Orioles (49-102, .325, -261 run-differential). They aren’t even really bad, like the Kansas City Royals (56-96, .368, -167 run-differential). They’re just bad (all records through Tuesday, September 17).
Despite their forgettable season, the Mariners have made a big difference in the AL West, where the Houston Astros have an 8-game lead over the Oakland A’s with two weeks left in the regular season.
The Astros have basically wrapped up the division. Their bigger concern now is their competition with the Yankees for the best record in the AL and home field advantage throughout the playoffs. The teams are tied at 99-53, but the Astros hold the head-to-head tie-breaker because they won the season series, four games to three.
The Astros have that 8-game lead over the A’s thanks in large part to their domination of the Mariners this season. They’ve played the M’s 17 times and have won 16 of those games. They’ve won big (21-1 on September 8) and they’ve won small (2-1 on September 7). They have five wins by five runs or more and eight wins by two runs or fewer, four of those in extra innings. Justin Verlander and Gerrit Cole each have three wins against the M’s, while Reymin Guduan has one—his only win in the big leagues.
Meanwhile, the Astros’ closest competitors in the division, the Oakland A’s, are a pedestrian 8-7 against the Mariners.
The A’s lost their first four games against the Mariners back in March and mid-May, when the Mariners were somewhat competent. By the time they faced each other again in late May, the Mariners had already dropped to last place in the AL West, 11.5 games out. The A’s have won eight of their last 11 games against the M’s.
The “Mariners Effect” can be seen by how the actual standings look compared to how they would look if the Astros and A’s didn’t play the Mariners this year.
Actual Standings:
99-53 Houston Astros
91-61 Oakland A’s (8 games behind)
Versus the Mariners:
16-1 Houston Astros
8-7 Oakland A’s
Standings Without Games Against the Mariners:
83-52 Houston Astros
83-54 Oakland A’s (1 game behind)
Without the games the Astros and A’s have played against the Mariners, the Astros’ 8-game lead would be just 1 game and the AL would have at least one exciting division race over the last two weeks of the season. As it is now, there’s kind of a race in the AL Central and a pretty good battle between three teams for two spots for the AL wild card.
Of course, the Mariners exist and the Astros and A’s had to play them this year, so you can’t just throw those games out. Still, even as good as the Astros are and as bad as the Mariners are, it’s unusual for the Astros to be 16-1 against them. We can replace that 16-1 record with a more reasonable estimate, then do the same for the A’s. With that in mind, what happens if we estimate how the Astros and A’s “should” have done against the Mariners this year?
There’s a mathematical way to consider this situation, keeping in mind the rest of this is hypothetical. Without their games against the Mariners, the Astros are 82-52, a .612 winning percentage, going into Monday. Without their games against the Astros, the Mariners are 61-72, a .459 winning percentage. Using a method from Bill James’ 1981 Baseball Abstract, we can determine how many games the Astros would be expected to win against the Mariners (warning: math ahead).
The formula:
P (X beats Y) = (p-pq)/(p+q-2pq), where p is the winning percentage of team X and q is the winning percentage of team Y. In this case, Team X is the Astros and Team Y is the Mariners. The Astros winning percentage from above is p and the Mariners winning percentage from above is q.
Team X=Astros
Team Y=Mariners
p=Astros’ winning percentage
q=Mariners’ winning percentage
Plugging in the winning percentages from above gives us this:
P (Astros beat Mariners) = (.612-.612*.459) divided by (.612+.459 -2*.612*.459) = .650.
The Astros would be expected to win 65 percent of their games against the Mariners. They’ve played them 17 times this year, so winning 65 percent of those games works out to 11 wins. They “should” be 11-6 instead of 16-1 against the Mariners.
Let’s do the same process with the A’s, again with numbers through the weekend. Without their games against the Mariners, the A’s are 82-53, a .607 winning percentage. Without their games against the A’s, the Mariners are 55-80, a .407 winning percentage.
Plugging in the winning percentages from above gives us this:
P (A’s beat Mariners) = (.607-.607*.407) divided by (.607+.407 -2*.607*.407) = .692.
The A’s would be expected to win 69 percent of their games against the Mariners. They’ve played them 15 times this year, so winning 69 percent of those games works out to 10 wins. They “should” be 10-5 instead of 8-7 against the Mariners.
Now we go back and plug in those new records versus the Mariners. The Astros in non-Mariner games are 82-52. Add in their new record against the Mariners, 11-6, and the Astros end up 93-58. The A’s in non-Mariner games are 82-53. Add in their new record against the Mariners, 10-5, and they end up 92-58, just a half-game out of first. In that hypothetical, math-based world, there’s quite an exciting pennant race happening in the AL West.
