What would be the biggest upset in the wildcard series in the MLB?

In the American League, the Tampa Bay Rays (the number 6 seed) play the Cleveland Guardians (the number 3 seed) and the Seattle Mariners (the number 5 seed) play the Toronto Blue Jays (the number 4 seed).

In the National League, the Philadelphia Phillies (the number 6 seed) play the St. Louis Cardinals (the number 3 seed) and the San Diego Padres (the number 5 seed) play the New York Mets (the number 4 seed).

First, let's look at the series between the Rays and Guardians. The Rays had a win-loss record of 86-76 and a win percentage of .531. The Guardians have a record of 92-70 and a win percentage of .568.

The next series is between the Mariners and Jays. The Mariners have a record of 90-72 and a win percentage of .556. The Jays have a record of 92-70 and a win percentage of .568.

Then we have the series between the Phillies and the Cardinals. The Phillies have a record of 87-75 and a win percentage of .537. The Cardinals have a record of 93-69 and a win percentage of .574.

Lastly, the series between the Padres and the Mets. The Padres have a record of 89-73 and a win percentage of .549. The Mets have a record of 101-61 and a win percentage of .623.

All series involve teams with significant differences in win percentages but the series between the Padres and the Mets has the biggest difference in win percentage by far. So based on purely win percentage stats, the most surprising outcome of the wild card series would be if the Padres beat the Mets.

While the Mets may have the biggest difference in win percentage, they are the only team in the wild card series that has both a higher win percentage and a losing record during the regular season against the team they are facing in the wild card series.

In my opinion, the biggest upset would be if the Rays beat the Guardians. The Guardians are first in the AL Central while the Rays are third in the AL East. The Guardians also have a winning record against the Rays during the regular season and have a much better win percentage.

So even though people would be surprised if the Mets lost the series against the Padres, I would be more surprised if the Rays beat the Guardians.