Lots of folks in and around baseball do not like interleague play. Baseball purists dislike interleague play because, well, it’s interleague. My favorite argument against interleague: American League pitchers shouldn’t have to bat because they might get hurt.
One objection I’ve heard a lot is that interleague play gives rise to unbalanced schedules for teams in the same division and those unbalanced schedules could give one team an advantage in the race for the division title or the wild card. The key word there is “could.” Since interleague play began during the 1997 season, there have been 42 divisional and and 14 wild card races in the National League.
I have concluded that only two National League divisional races and only one National League wild card race between teams in the same division may have been affected by an unbalanced interleague schedule:
(1) 2006 NL Central race between the St. Louis Cardinals, the Houston Astros, and the Cincinnati Reds. The Cardinals won the division by 1.5 games over the Astros and by 3.5 over the Reds.
(2) 2007 NL Central race between the Milwaukee Brewers and Chicago Cubs. The Cubs won the division by 2 games over the Brewers.
(3) 2007 wild card race between NL West rivals the San Diego Padres and the Colorado Rockies. The Rockies won the wild card by 1 game over the Padres.
My methodology: I reviewed the final National League standings for each season between 1997-2010. I identified those division races and wild card races between teams in the same division where the margin of victory for the division/wild card winner was less than 4 games. I did not focus on close wild card races between teams in different divisions because those teams already have very different schedules, which makes assessing the affect of unbalanced interleague schedules difficult (at least for this blogger). Here is the list I started with:
National League Division and Wild Card Races 1997-2010 Where Margin of Victory Was Less Than 4 Games
Race Winner (Interleague Record) Loser (Interleague Record) Margin of Victory
1997 National League West San Francisco Giants (10-6) Los Angeles Dodgers (9-7) 2 games
2001 National League East Atlanta Braves (9-9) Philadelphia Phillies (7-11) 2 games
2001 National League West Arizona Diamondbacks (7-8) San Francisco Giants (10-5) 2 games
2002 National League Wild Card San Francisco Giants (10-8) Los Angeles Dodgers (12-6) 3.5 games
2003 National League Central Chicago Cubs (9-9) Houston Astros (11-7) 1 game
2003 National League Central Chicago Cubs (9-9) St. Louis Cardinals (10-8) 3 games
2004 National League West Los Angeles Dodgers (10-8) San Francisco Giants (11-7) 2 games
2006 National League Central St. Louis Cardinals (5-10) Houston Astros (7-11) 1.5 games
2006 National League Central St. Louis Cardinals (5-10) Cincinnati Reds (6-9) 3.5 games
2007 National League East Atlanta Braves (4-11) New York Mets (8-7) 1 game
2007 National League Central Chicago Cubs (8-4) Milwaukee Brewers (8-7) 2 games
2007 National League Wild Card Colorado Rockies (10-8) San Diego Padres (6-9) 1 game
2008 National League East Philadelphia Phillies (4-11) New York Mets (8-7) 3 games
2010 National League West San Francisco Giants (7-8) San Diego Padres (9-6) 2 games
I then eliminated those races where the teams had the same interleague schedule: 1997 National West race between the Giants and the Dodgers and 2001 National League East race between the Braves and the Phillies.
After that, I eliminated those races where the loser had a better interleague record than the winner by a differential greater than the margin of victory for the winner:
(1) 2001 National League West race between the Diamondbacks and the Giants
(2) 2002 Wild Card race between the Giants and the Dodgers
(3) 2007 National League East race between the Braves and the Mets
(4) 2008 National East race between the Phillies and the Mets
I didn’t include the 3-way race in the National League Central from 2003 in the above list because the race was as close as the interleague records. I wanted to look at that one more closely. I also had 6 other races to analyze. Here’s what I found.
2003 National League Central race:
The Cubs won the Central in 2003 by 1 game over the Astros and 3 games over the Cardinals. The Cubs had the worst interleague record of the three teams (9-9) and the toughest interleague schedule. The NL Central played the AL East in 2003. The Cubs missed the Boston Red Sox (who were 95-67) in order to play 6 games against the rival Chicago White Sox (who were 86-76 that season). The Cubs won only 2 games against the White Sox, losing 4.
The Astros had the best interleague record of the 3 teams, even though the Astros had to play both the Red Sox and the New York Yankees (who were 101-61 that season). The Astros missed the Toronto Blue Jays (86-76) in order play 6 games against in-state rival Texas Rangers (who were awful at 71-91). Astros went 4-2 against the Rangers.
The Cardinals had the second best/worst interleague schedule (10-8) and the second easiest/hardest interleague schedule. The Cardinals missed the Yankees in order to play 6 games against the Kansas City Royals. But the Royals were ok in 2003 (83-79), certainly better than the Rangers.
My conclusion: The unbalanced interleague schedule did not hurt the Astros and the Cardinals in the 2003 National League Central race.
2004 National West race:
This one is easy. The Giants finished 2 games behind the Dodgers in 2004. The Giants won 1 more interleague game than the Dodgers did but had the much easier interleague schedule. The NL West played the AL East in 2004. The Giants skipped the Yankees (101-61) in favor of 6 games with the rival Oakland A’s. The Dodgers skipped the Tampa Bay Devils Rays (70-91) in favor of 6 games with the Anaheim Angels. The Angeles and A’s had nearly identical records. The Giants and Dodgers each won 3 and lost 3 of the games against their rivals.
My conclusion: The Dodgers had the tougher interleague schedule, the worse interleague record, and won the division.
2006 National League Central race:
This one is interesting. The Cardinals won the division over the Astros by 1.5 games and the Reds by 3.5 games. The Cardinals and the Reds each played 15 interleague games against the same opponents (White Sox, Indians, Tigers and Royals) but the Cardinals played 6 against the rival Royals and the Reds played 6 against the rival Indians. The Cardinals went 4-2 against the Royals, while the Reds went 3-3 against the Indians. The Cardinals otherwise played poorly in interleague games, and ended with a worse interleague record (5-10). So I don’t see how interleague hurt the Reds in 2006 vis a vis the Cardinals.
But the Astros played 3 more interleague games than either the Cards or the Reds. All three teams played the Royals, the White Sox and the Tigers. But the Astros also played 3 against the Minnesota Twins and 6 against in-state rival Texas Rangers. The Twins were 96-66 in 2006 and won the AL Central. The Rangers were 90-72 and won the AL West.
My conclusion: The Astros had the toughest interleague schedule of the 3 teams and missed the playoffs by only 1.5 games. The unbalanced interleague schedules may very well have affected the outcome of this divisional race.
2007 National League Central race:
The Cubs beat the Brewers by 2 games to win the NL Central title in 2007. The Brewers played 3 more interleague games in 2007 than the Cubs did. The Cubs played the White Sox (and went 5-1), the Rangers (1-2), and the Mariners (2-1) for an overall interleague record of 8-4. The Brewers played the Tigers (2-1), the Royals (2-1), the Twins (3-3) and the Rangers (1-2), for an overall interleague record of 8-7. When the NL Central “matches up” with the AL West in interleague, the schedules are at their most unbalanced because the NL Central has 6 teams and the AL West only has 4.
Of all the AL teams played by the Brewers and Cubs in 2007, only the Tigers and the Mariners had winning records for the season. The Twins (who the Brewers played 6 times) were only slightly better than the White Sox (who the Cubs played 6 times). That leaves the Brewers’ 3 games against the Royals, who were 69-93 in 2007.
My conclusion: The unbalanced interleague schedule may have played a role in the Cubs’ victory over the Brewers in the NL Central in 2007. To reach a more definitive conclusion, I’d have to look at the Cubs’ and the Brewers’ entire schedules for 2007. Stay tuned on that one.
2007 National League Wild Card race:
The Colorado Rockies beat out the San Diego Padres for the NL wild card in 2007 by 1 game. (The Rockies won 21 out of 22 games in the final 3 weeks of the season to make the playoffs). The Rockies were 10-8 in interleague play; the Padres were 6-9. Both teams played 3 games each against the Orioles, the Red Sox and the Devil Rays. The Padres then played 6 games against the Mariners, who were 88-74 that season. The Rockies played 3 each against the Royals (69-93), Yankees (94-78) and the Blue Jays (83-79).
At first blush, you’d think the 3 games against the Royals may have tipped in the scales toward the Rockies in this wild card race. But the Rockies went 1-2 against the Royals, while they took 3 from the Yankees and lost 3 to the Blue Jays.
My conclusion: The unbalanced interleague schedule may have played a role in the Rockies 1 game victory over the Padres in the NL wild card in 2007. To reach a more definitive conclusion, I’d have to look at the full season schedules for the Rockies and the Padres. Stay tuned on that one.
2010 National League West race:
The Giants clinched the NL West on the last day of the 2010 season, beating out the Padres by 2 games. The Padres (9-6) had a better interleague record than the Giants (7-8). Both teams played the Orioles and the Blue Jays. The Padres then played 3 against the Rays (going 2-1) and 6 against the Mariners (going 4-2). The Giants played 3 against the Red Sox (going 1-2) and the 6 against the A’s (going 3-3). Neither team had to play the Yankees.
The Padres’ 6 games against the Mariners gave them a big advantage, as the Mariners suffered through one of their worst seasons in 2010 (61-101). The A’s, on the other hand, ended the season with a .500 record. The Padres did better against the Rays than the Giants did against the Red Sox, even though the Rays were the better team in 2010.
My conclusion: The unbalanced interleague schedule did not affect the NL West division race in 2010.
If you’ve read to the end of this long post, thank you. The post on the effect of interleague play on American League races will be much shorter because the great majority of American League races between 1997-2010 were decided by more than 4 games.