Interleague play is the term used to describe regular season Major League Baseball games played with teams in different leagues, introduced in 1997. Before the 1997 season, teams in the American League and National League did not meet during the regular season. AL/NL matchups only occurred during spring training, the All-Star Game, the exhibition Hall of Fame Game in Cooperstown, New York, and the World Series. All of those were considered exhibition games, with the exception of the World Series.
Interleague or interconference matchups have long been the norm in other professional sports leagues such as the NFL. But while regular season interleague play was discussed for baseball's major leagues as early as the 1930s, the concept didn't take hold until the 1990s (at least in part as an effort to renew the public's interest in MLB following the controversial 1994 players' strike). Interleague play was not, and is still not, a universally endorsed innovation. However, it has added a new dimension to the major-league game, creating some matchups that had not been seen before, and some which held special significance for geographical and historical reasons.
The first interleague game took place on June 12, 1997, as the Texas Rangers hosted the San Francisco Giants at The Ballpark in Arlington (now Ameriquest Field in Arlington). There were four interleague games on the schedule that night, but the other three were played on the West Coast, so the Rangers-Giants matchup started a few hours earlier than the others.
From 1997 to 2001, teams from the American League West played teams from the National League West, etc., typically scheduled to alternate between home and away in consecutive years. However, in 2002, the league began alternating which divisions would play which divisions, and thus in 2002 the American League East played the National League West, the American League Central played the National League East, and the American League West played the National League Central. Matchups which had been of particular interest prior to this format — mainly geographic rivals — were preserved. This is expected to be the continuing format of the interleague schedule though corresponding divisions were integrated in this rotation in 2006.
The designated hitter (DH) rule is applied in the same manner as in the World Series and the All-Star Game. In an American League ballpark, both teams use a DH to hit for the pitcher. In a National League ballpark, both teams' pitchers must bat. Some baseball observers feel it might be fairer to reverse this (in other words, always follow the DH rule of the visiting team instead of the home team), thereby offsetting the home-field advantage.
Until 2006, the National League held an 1104-1095 advantage over the American League as of 2005, although in 2006 the American League was dominant in interleague play with a 154-98 record bringing the record to 1249-1202. The best record in Interleague play is the New York Yankees of the American League with a record of 103-71, just a game ahead of the Oakland A's who previously held the record (currently 103-73).
Several interleague matchups are highly anticipated (and well-attended), for a number of reasons:
- New York Yankees v. New York Mets (Subway Series)
- Chicago White Sox v. Chicago Cubs (Crosstown Classic, Windy City Series, or Red Line Series)
- Los Angeles Angels of Anaheim v. Los Angeles Dodgers (Freeway Series)
- Oakland Athletics v. San Francisco Giants (Bay Bridge Series)
- Tampa Bay Devil Rays v. Florida Marlins (Citrus Series)
- Cleveland Indians v. Cincinnati Reds (Battle for Ohio or Buckeye Series)
- It has been reported in some circles that Cleveland has requested to change its interleague "natural rivalry" opponent to the Pittsburgh Pirates, as the two cities are fierce rivals in football.
- Kansas City Royals v. St. Louis Cardinals (I-70 Series or Show-Me Series)
- Texas Rangers v. Houston Astros (Lone Star Shootout)
- Baltimore Orioles v. Washington Nationals (Beltway Series, Battle of the Beltway, or Potomac Series)
- Because the 2005 MLB schedule was already set when the Montreal Expos moved to Washington, DC, the Orioles did not play the Nationals during the 2005 regular season. The two teams began their rivalry in 2006, and play home-and-home series each year during interleague play.
- Minnesota Twins v. Milwaukee Brewers
- Boston Red Sox v. New York Mets
- This matchup is remembered mainly because of the 1986 World Series. In the 10th inning of Game 6 of this Series, the Red Sox came within one strike of their first World Series win since 1918 before losing the lead. Later in the inning, the winning run scored after a ground ball went between the legs of first baseman Bill Buckner. The Mets went on to win Game 7 and the Series.
- Toronto Blue Jays v. Atlanta Braves
- The Braves were the Jays' victim when they became the first Canadian team to win the World Series, in 1992.
- Toronto Blue Jays v. Philadelphia Phillies
- The Phillies were the Jays' victim the second time around in 1993 when Joe Carter hit the series-winning home run off of Mitch Williams in the bottom of the ninth inning to give the Jays their second consecutive World Series title.
- New York Yankees v. Atlanta Braves
- These teams have met four times in the World Series. In 1957 and 1958, when the Braves played in Milwaukee, the teams went to seven matches both times, with the Braves winning the first time and the Yankees winning the second. In 1996 and 1999, the Yankees and Braves renewed their old rivalry from the late 1950s; the Yankees won both times, sweeping the Braves in 1999.
- New York Yankees v. Los Angeles Dodgers
- This rivalry goes back to the days when both teams played in New York. Between 1941 and 1956, the two teams played in seven World Series; Brooklyn won only once (1955). After the Dodgers moved from Brooklyn to Los Angeles, the teams played four more times in the World Series, with each team winning twice (Dodgers in 1963 and 1981, Yankees in 1977 and 1978).
- Minnesota Twins v. Los Angeles Dodgers
- This matchup was a rematch of the 1965 World Series, which the Dodgers won in seven games. The Twins and Dodgers met a second time in Los Angeles in June 2005, the fortieth anniversary of the 1965 series. The Twins took two out of three in this series. They then met again in Minnesota in June of 2006, with the Twins winning all three games.
- Boston Red Sox v. Chicago Cubs
- In 1918, these two teams went against each other in the World Series. The Cubs fell victim as the Red Sox took their last World Series title before taking it again 86 years later.
- Toronto Blue Jays v. Montreal Expos
- From 1978 to 1986, the teams only met in the charity Pearson Cup in mid-season. They would only have met in relevant play had they both won their leagues' pennants. They played Pearson Cup games again in 2003, only as exhibition games. As the only Canadian teams, it made a natural rivalry that ended with the Expos' move to Washington.
- Boston Red Sox v. Atlanta Braves
- Until 1953, Boston was a two-league town and the Braves were Boston's National League team. But they moved to Milwaukee in 1953, and then to Atlanta in 1966. The rivalry between these two former crosstown rivals was limited to spring training before interleague play, and has become a tradition during the regular season now.
- Philadelphia Phillies v. Oakland Athletics
- Until 1954, Philadelphia was a two-league town and the Athletics were Philadelphia's American League team. The A's moved to Kansas City in 1955, and then to Oakland in 1968. Now these two teams, who for about 50 years were crosstown rivals, occasionally face each other during the regular season.
- St. Louis Cardinals v. Baltimore Orioles
- Until 1953, St. Louis was a two-league town and the Browns were St. Louis' American League team. They moved to Baltimore in 1954 and became the Orioles. Interleague play rekindles this five-decade crosstown rivalry.
- San Francisco Giants v. Los Angeles Angels of Anaheim
- This was the pairing that competed in the 2002 World Series, in the first ever meeting of two wild card teams for the world championship. The series was marked by dramatic, high-scoring games and come-from-behind victories, and many Giants fans believe that Barry Bonds should have been named MVP instead of the Angels' Troy Glaus, who was awarded the honor instead.
- Los Angeles Dodgers v. Oakland Athletics
- These two teams have met twice in the World Series, and each team has a victory apiece. The A's defeated the Dodgers in 1974 to win the last of their three consecutive world championships, but the Dodgers would get their revenge in the '88 Series, which is best known for Kirk Gibson's walkoff pinch-hit home run in Game 1.
- Boston Red Sox v. New York Mets
- Interleague matchplay increases attendance.
- Fans can see players they might not otherwise get to see, especially those who have only ever played in one league, such as Barry Bonds, Alex Rodriguez, Greg Maddux, etc..
- Certain geographic rivalries are played out during the regular season that otherwise might not happen for years at a time, such as Chicago Cubs v. Chicago White Sox.
- It creates matchups that might not have been seen in generations. For example, during the 2004 season, the Giants and Red Sox played each other for the first time since meeting in the 1912 World Series.
- Since a few more games are played against non-divisional opponents than before, there is a better chance for a last place team to catch up with the teams in front of it in its own division, even with very few games remaining in the season. Combined with the divisional realignment of 1994 (which now sends three divisional winners and one wild card from each league to the post-season), more teams remain in the running to qualify for the post-season, and they remain in the running longer. In other words, teams are less likely to be mathematically eliminated as early in the season as they used to be, so fan interest is probably stronger.
- It allows for a rematch of the World Series. This has occurred in six of the ten seasons of interleague play: 1997 (Atlanta Braves at New York Yankees), 2000 (New York Yankees at Atlanta Braves), 2001 (New York Mets vs. New York Yankees), 2002 (Arizona Diamondbacks at New York Yankees), 2005 (Boston Red Sox at St. Louis Cardinals), 2006 (Houston Astros at Chicago White Sox) and 2006 (Florida Marlins at New York Yankees).
- There are many series that are not considered compelling; for example, series between currently poor-performing teams with no historical or geographic connections.
- American League pitchers generally don't like taking batting practice for the opportunity to bat in one or two games. These pitchers are also unaccustomed to running the bases, which can lead to injury and premature fatigue.
- With the two leagues not having the same number of teams, and with one division (the National League Central) containing six teams while another (the American League West) has only four (the other two divisions in both leagues consisting of five teams each), various irregularities in scheduling result. Most notably, teams no longer play identical opponents as their divisional rivals, and even where they do, they don't always play them an identical number of times. This can lead to "strength of schedule" disparities like those the NFL has to deal with on a yearly basis. For example, in any given season, one NL Central team might play every AL East team except the (strong) first place team, while another NL Central team plays all but the (weak) last place team. Another scheduling problem is that because the leagues are not equal in size, there always has to be one national league game on interleague days (interleague is done with block scheduling like the NHL, so all the teams play interleague games on the same day, and all the interleague games are played in one part of the schedule (third weekend of may and most of June)
- The "rivalry" series that consist of six games a year for some teams leads to further scheduling inequities. For example, the Chicago Cubs play the recently solid Chicago White Sox six times a year, while their division rival St. Louis Cardinals play the recently poor Kansas City Royals six times a year.
- The World Series and All-Star game are robbed of some of their mystique that used to result from the two leagues playing completely exclusive schedules during the regular season.
- List of Major League Rivalries
- MLB.com: Interleague stats through 2005
- Proposals for interleague play prior to 1997
- For head to head listings, choose team and the time period to get full list and results