|Born: December 1, 1952|
|May 18, 1975, for the Montreal Expos|
|Last MLB appearance|
|September 29, 1978, for the Houston Astros|
|Earned run average||4.31|
Daniel Dean Warthen (born December 1, 1952) is an American former professional baseball player and current coach for the Texas Rangers. He played in Major League Baseball (MLB) as a left-handed pitcher from 1975 to 1978 for the Montreal Expos, Philadelphia Phillies, and the Houston Astros.
Warthen was born in Omaha, Nebraska, and is Jewish. He attended Omaha North High School in Omaha, graduating in 1971, and was a high school All-American quarterback, tight end, and linebacker in football and also a star in baseball. He was the 1971 co-winner of the B'nai B'rith Award. In 2018 he was inducted into the Omaha Public Schools Athletic Hall of Fame.
Warthen was drafted by the Montreal Expos in the 2nd round of the 1971 Major League Baseball Draft. He pitched first for the Watertown Expos in the 1971 Northern League, and was 9-3 with a 3.96 ERA, leading the league with 10 complete games and second in the league in wins.
He made his Major League Baseball debut as a 22 year-old with the Expos on May 18, 1975, pitching a scoreless eighth inning against the Cincinnati Reds. In his rookie season in 1975, Warthen was 8-6 with three saves and a 3.11 ERA in 167.2 innings over 40 games (18 starts), and was 3rd in the National League in hits per 9 IP (6.978) and 4th in strikeouts per 9 IP (6.871).
Warthen pitched four seasons in the major leagues with Montreal, Philadelphia, and Houston. He finished his major-league career with a 12–21 win–loss record and a 4.31 ERA.
Warthen began his coaching career with the Pittsburgh Pirates in 1981, following that with coaching in the minor league organizations of San Diego and Philadelphia. Warthen was the pitching coach for the Detroit Tigers (1999–2002), San Diego Padres (1996–97), and Seattle Mariners (1992), also serving as the Mariners bullpen coach in 1991. He was the pitching coach for the Triple A Norfolk Tides from 2003–2005.
Warthen served as the bullpen coach for the Los Angeles Dodgers under manager Grady Little from 2006–2007. On June 17, 2008, Warthen was named the New York Mets pitching coach, replacing Rick Peterson. In the 2012 off-season rumors speculated that Warthen would not return due to the staff changes, but he stayed along with then hitting coach Dave Hudgens. In 2014, Warthen used the slur "Chinaman" in a conversation with an Asian-American interpreter in the clubhouse. He later issued an apology.
Warthen was relieved of his coaching position by the Mets on October 3, 2017, but was offered another role with the organization, which he declined.
On November 6, 2017, Warthen was hired by the Texas Rangers as the assistant pitching coach.