"MMMBop" is a song written and performed by the American pop rock band Hanson and released as the lead single from their debut full length studio album, "Middle of Nowhere", in 1997.
 The song was nominated for two Grammys at the 40th Annual Grammy Awards in February 1998 and is the band's most successful single to date.
 "MMMBop" was phenomenally successful, especially for a debut single, reaching number one in 27 countries including the United States, the United Kingdom, Germany, Australia and Mexico.
 In the United Kingdom, the song sold 710,000 copies and stayed at number one for 3 weeks.
Raymond Leonard Culp (born August 6, 1941 in Elgin, Texas) is a retired baseball pitcher who pitched for Major League Baseball's Philadelphia Phillies (1963–66), Chicago Cubs (1967), and Boston Red Sox (1968–73).
Kevin Andrew Saucier (born August 9, 1956) was a Major League Baseball pitcher from 1978 to 1982 for the Philadelphia Phillies and Detroit Tigers.
 Nicknamed "Hot Sauce", Saucier (whose name is pronounced "So-Shay"), was an energetic pitcher who would often display his emotions while on the mound.
 Saucier retired prior to the 1983 season due to his loss of control on the mound leading him to fear that he might kill someone with a pitch.
Lee Mallory (January 10, 1945 – March 21, 2005) was a singer, songwriter and guitarist who was part of such projects as The Millennium and Sagittarius.
 His most successful single was a cover of the Phil Ochs/Bob Gibson song "That's The Way It's Going To Be".
 The song, produced by Curt Boettcher, reached #86 on the charts and was a surprise hit in Seattle.
 A CD by the same name was released in 2002, with many songs and demos Mallory had recorded during the 60s.
 Lee Mallory helped start it all: the California Sound of the 1960s.
Robert Gibson (born November 9, 1935) is a retired American baseball pitcher who played 17 seasons in Major League Baseball (MLB) for the St. Louis Cardinals (1959–75).
 Nicknamed "Gibby" and "Hoot", Gibson tallied 251 wins, 3,117 strikeouts, and a 2.91 earned run average (ERA) during his career.
 A nine-time All-Star and two-time World Series champion, he won two Cy Young Awards and the 1968 National League (NL) Most Valuable Player (MVP) Award.
 In 1981, he was elected to the Baseball Hall of Fame in his first year of eligibility.
 The Cardinals retired his uniform number 45 in September 1975 and inducted him into the team Hall of Fame in 2014.
Hubert Milton "Hub" Kittle (February 19, 1917 – February 10, 2004) was an American professional baseball pitcher, manager and front office executive in the minor leagues and a pitching coach at the Major League level.
 When he took the mound for the Triple-A Springfield Redbirds in an official American Association game on August 27, 1980, at the age of 63, Kittle, a longtime minor league hurler whose professional career began in the 1930s, became the only man ever to pitch in professional baseball in six decades.
 He retired the Iowa Oaks on 11 pitches.
Robert Max "Sugar" Cain (October 16, 1924 – April 8, 1997) was an American Major League Baseball pitcher with the Chicago White Sox, Detroit Tigers and St. Louis Browns between 1949 and 1954.
 He batted and threw left-handed.
 Cain was the pitcher who issued a base on balls to Eddie Gaedel, whose single plate appearance made him the shortest person to appear in a major league game.
Terrence Richard Ley (born 21 February 1947, Portland, Oregon) is a retired baseball pitcher who began his career in the 1971 season for the New York Yankees.
 He was a student of University of Oregon before he was drafted in the 3rd round of the January 1967 draft and was 24 when he made his major league debut on August 20, 1971 for the Yankees.
 He played in 6 major league games.
Donald Joseph Stanhouse (born February 12, 1951 in Du Quoin, Illinois) is a retired baseball pitcher who had a ten-year major league career from 1972 to 1980, 1982.
 He played for the Texas Rangers and Baltimore Orioles of the American League and the Montreal Expos and Los Angeles Dodgers of the National League.
David Earl "Dave" Stapleton (born October 16, 1961, in Miami, Arizona) is a retired professional baseball pitcher whose career spanned six seasons, two of which were spent in Major League Baseball (MLB) with the Milwaukee Brewers (1987–88).
 The majority of Stapleton's career was spent in the minor leagues.
 His career began in 1984 with the Class-A Beloit Brewers of the Midwest League.
 During his minor league career, Stapleton compiled a 30–26 record with a 3.43 earned run average (ERA) in 444 innings pitched.
 Over his two years in the majors, he compiled a 2–0 record with a 3.81 ERA and 20 strikeouts in 28⁄ innings pitched.
 Stapleton batted and threw left-handed.
 During his professional career, he was listed at a height of 6 ft and a weight of 185 lb .

Question: Whose most successful single was a cover of a song written by a retired baseball pitcher?
Answer: Lee Mallory