In baseball, the designated hitter rule is the common name for Major League Baseball Rule 6.10, an official position adopted by the American League in 1973 that allows teams to designate a player, known as the designated hitter (abbreviated DH), to bat in place of the pitcher each time he would otherwise come to home plate, rather than replace him by pinch-hitting. Since then, most collegiate, amateur, and professional leagues have adopted the rule or some variant; MLB's National League, NPB's Central League, and the independent Golden Baseball League are the most prominent professional leagues that have not.
In professional and collegiate play, the designated hitter cannot be used for any other player but the pitcher; more liberal rules exist in lower levels of amateur play (see below). In any case, use of the DH is optional, however, the manager must designate a DH prior to the start of the game; failure to do so forfeits the right to use the DH, and the pitcher must then take his turn at bat. The designated hitter may not play a field position and he may only be replaced by another player not currently in the lineup. However, the designated hitter may become a position player at any point during the game; if he does so, his team forfeits the role of the designated hitter, and the pitcher or another player (possible only in case of a multiple substitution) must bat in the newly opened spot in the batting order. The designated hitter could also become the pitcher, in which case any subsequent pitcher, or a pinch hitter, must hit when that spot in the batting order comes up again (save for a further double switch, as above). Likewise, if a pinch-hitter bats for some other player (such as, hypothetically, the first baseman) and then remains in the game as the pitcher, the team would forfeit the use of the DH for the remainder of the game, and the DH would have to assume a field position (in this hypothetical, play first base save, of course, for switching defensive positions with a teammate(s)).
In addition, unlike other positions, the DH is "locked" into the batting order and no multiple substitution may be made to alter the batting rotation of the DH. In other words, a double switch involving the DH and a position player is not legal. For example, if the DH is batting fourth and the catcher is batting eighth, the manager cannot replace both players so as to have the new catcher bat fourth and the new DH bat eighth. Once a team loses its DH under any of the scenarios discussed in the previous paragraph, however, the double switch becomes fully available, and may well be used via necessity, should the former DH be replaced in the lineup.
If a pinch-hitter bats, or a pinch-runner runs, for the DH, he then becomes the DH.
In Major League Baseball, (for interleague play and the World Series), the home team is the determining factor, with the rules of the home team's league applying to both teams; if the game is played in an American League park the designated hitter is in effect, however, in a National League park the pitcher must bat or be replaced with a pinch hitter.
This has applied to the All-Star Game as well, but in 2010, Major League Baseball announced the designated hitter rule would apply for every All-Star Game; while the 2010 game was already to have the DH, the 2011 game will be the first played in a National League park with a DH.
Forfeiting the right to a DH
In practice, it is very rare for a team to forfeit its right to a DH, even by substitution. The following are known instances in regular season games (not counting interleague play) of an American League pitcher coming to bat:
- On September 5, 1976, New York Yankees starting pitcher Catfish Hunter pinch-hit for second baseman Sandy Alomar, Sr. in top of the 6th inning and stayed in the lineup as the pitcher for the Yankees in the bottom half of the inning. Cesar Tovar, the one-time designated hitter in the game, then took over at second base. (Note: There is now a section of the rule that states that the game pitcher may only pinch-hit for the designated hitter; therefore, this move would have been allowed then, but now it would be prohibited.)
- In his first of three major league pitching appearances for the Toronto Blue Jays, Bob Bailor, normally a position player, was moved from shortstop to pitcher in the 7th inning in a game on August 4, 1980. Bailor finished out the game at pitcher. The DH position was lost, and pitcher Bailor came to bat in the ninth and popped out.
- During the month of September, 1980, Baltimore Orioles manager Earl Weaver inserted a pitcher into the DH slot but would use a hitting specialist (such as Benny Ayala or Terry Crowley) to pinch-hit when the designated hitter's first turn came up. There was a game on September 17, 1980, during which the Orioles and the Detroit Tigers both used the short-lived strategy. (Note: Due to the loophole of which Earl Weaver took advantage, there was a rule change shortly thereafter that states the DH must come to bat at least once, unless the opposing team changes pitchers.)
- On September 26, 1987, Detroit Tigers designated hitter Darrell Evans moved to first base in the bottom of the seventh inning in a game against the Toronto Blue Jays, causing pitcher Mike Henneman to be inserted into the first baseman's spot in the batting order. Henneman batted for himself in the ninth, but struck out attempting to bunt. The Blue Jays scored three runs in the bottom of the ninth to win the game 10-9, with Henneman taking the loss.
- In the bottom of the 8th on July 15, 1993, the Seattle Mariners' Jeff Nelson was moved from the pitcher position to left field. The strategy allowed Nelson to stay in the game while left-handed pitcher Dennis Powell came in to pitch to Mike Greenwell in a game at Boston. By moving the pitcher into a defensive position, Nelson was put into the designated hitter's spot in the batting order while the new pitcher (Powell) was placed into the left fielder's place in the batting order. (It is very uncommon to see this particular move in an American League ballgame due to the DH.) Powell's turn in the batting order came up in the top of the ninth: Pete O'Brien pinch hit for him. Left fielder Nelson was then moved back to pitcher, and pitched in the bottom of the ninth.
- An unusual instance of an American League team forfeiting its right to the DH happened on July 22, 1999 to the Cleveland Indians in a game against the Toronto Blue Jays. Manny Ramirez, the designated hitter, accidentally went into right field instead of Alex Ramirez causing some confusion. The Indians lost their DH, and Charles Nagy was forced to hit in Alex Ramirez's place going 0 for 2. John McDonald later pinch-hit for Nagy in the 6th inning.
- On August 10, 1999, the Tampa Bay Devil Rays brought in third baseman Wade Boggs to pitch against the Baltimore Orioles in a blowout in favor of Baltimore. Boggs, peculiarly, was put into the DH's place in the lineup at the same time he was being brought into the game to pitch. Pitcher Boggs grounded out in his only at bat.
- There have been times when a manager may willingly surrender the DH position late in a game. During the 2005 American League Division Series between the New York Yankees and the Los Angeles Angels of Anaheim, New York had Bernie Williams slated as the designated hitter. Late in the game, manager Joe Torre took Williams out of the DH and put him in center field because of Williams' superior defensive play. Since the Yankees already had the lead, not giving up any more runs was more important to Torre than having a better hitter hit for the pitcher in the game at the time, Yankees closer Mariano Rivera. Because a double switch was used, it was not necessarily a negative situation to have Rivera bat. Rivera's place in the order would have only come up if the Yankees batted around, which would have inherently meant their lead would have been further increased at that late point in the game anyway, giving more cushion for the Yankees' best relief pitcher to close out the game.
- In the second game of a doubleheader between the Minnesota Twins and Chicago White Sox on July 6, 2007, the Twins initially used their starting catcher, Joe Mauer, as the DH because Mauer had started the first game at catcher. The starting catcher for the second game, Mike Redmond, however, was forced to leave the game in the first inning due to injury after accidentally being struck in the head by the bat of Jim Thome, and Mauer had to take the field as the replacement catcher. Twins starting pitcher Matt Garza thus was forced into the batting order and became the first American League pitcher to bat in a regular-season American League game since Hipolito Pichardo on July 31, 2000.
- On May 19, 2008, the Minnesota Twins surrendered their DH position in a game vs. the Texas Rangers in Minneapolis. Twins Manager Ron Gardenhire had to use rookie pitcher Bobby Korecky as a hitter in the 11th inning of the game; Korecky had only pitched in five major league games prior to this and had never had a major league at-bat. Nevertheless, Korecky hit the first pitch he saw into right field for a single, becoming the first Twins pitcher to get a hit in an American League game since the implementation of the DH rule. The inning ended with Korecky stranded at 3rd base with the bases loaded. Korecky ended up getting his first major league win in this game as the Twins won 7-6 in 12 innings.
- On May 17, 2009, Tampa Bay Rays manager Joe Maddon incorrectly listed both Ben Zobrist and Evan Longoria as third basemen in the starting lineup against the Cleveland Indians. Maddon's intent was for Zobrist to play at third and Longoria to be the DH. In the middle of the first inning, Cleveland manager Eric Wedge brought Maddon's error to the umpires' attention, and the Rays were forced to forfeit their DH, remove Longoria from the lineup since Zobrist played the top half of the first inning at third base (Longoria was available as a substitute since he never appeared in the game before that point), and bat starting pitcher Andy Sonnanstine at Longoria's place in the order—third. This was the first time a pitcher was in the initial batting order in a game between two American League teams since the aforementioned Ken Brett. Sonnanstine went 1 for 3 with an RBI double.
- On May 28, 2009, Minnesota Twins catcher Mike Redmond was ejected from a game in Minneapolis against the Boston Red Sox after disputing umpire Todd Tichenor's call on a close play at home plate. Because Minnesota's normal starting catcher Joe Mauer was in the game as the DH and no other catcher was available, Minnesota was forced to forfeit the DH position for the remainder of the game. The pitcher was replaced with a pinch hitter both times it came up in Boston's 3-1 victory.
- On October 19, 2009, in the ALCS Game 3 New York Yankees designated hitter Jerry Hairston replaced left fielder Johnny Damon in the outfield in the 10th inning. This move forfeited their designated hitter and made the pitcher spot come up third in the 11th inning.
- On September 13, 2010, Tampa Bay Rays catcher Kelly Shoppach was replaced by pinch-runner Desmond Jennings after Shoppach was hit by a pitch in the bottom of the 8th in a tight pitchers duel between the Rays' David Price and the Yankees' CC Sabathia. Dioner Navarro moved from designated hitter to catcher to start the 9th inning, thereby sacrificing Tampa Bay's designated hitter. By the time the DH spot was due up to bat in the 10th inning, pitcher Joaquin Benoit was pinch-hit for by Dan Johnson, who singled to right field.