Mark David McGwire (born October 1, 1963), nicknamed "Big Mac", is an American former professional baseball first baseman. His Major League Baseball (MLB) playing career spanned from 1986 to 2001 while playing for the Oakland Athletics and the St. Louis Cardinals, winning one World Series championship each, with Oakland as a player in 1989 and with St. Louis as a coach in 2011. One of the most prolific home-run hitters in baseball history, McGwire holds the major-league career record for at-bats per home run ratio (10.6), and is the former record holder for both home runs in a single season (70 in 1998) and home runs hit by a rookie (49 in 1987).

McGwire ranks 11th all-time in home runs with 583, led the major leagues in home runs in five different seasons and set the major-league record for home runs hit in a four-season period from 1996 to 1999 with 245. He demonstrated exemplary patience as a batter, producing a career .394 on-base percentage (OBP) and twice leading the major leagues in bases on balls. Injuries cut short even greater potential, as he reached 140 games played in just eight of 16 total seasons. A right-handed batter and thrower, McGwire stood 6 feet 5 inches (1.96 m) tall and weighed 245 pounds (111 kg) during his playing career.

With the Cardinals in 1998, McGwire joined Cubs slugger Sammy Sosa in a chase for the single-season home-run record set by Roger Maris in 1961. McGwire surpassed Maris and finished with 70 home runs, a record that Barry Bonds would break three years later with 73. McGwire also led the league in runs batted in, twice in bases on balls and on-base percentage and four times in slugging percentage. Injuries significantly cut into his playing time in 2000 and 2001 and factored into his decision to retire. He finished with 583 home runs, which was fifth all-time when he retired.McGwire was one of several central figures in baseball's steroids scandal. In 2010, McGwire publicly admitted to using performance-enhancing drugs during a large portion of his career.

Barry Lamar Bonds (born July 24, 1964) is an American former professional baseball left fielder who played 22 seasons in Major League Baseball (MLB). Bonds was a member of the Pittsburgh Pirates from 1986 to 1992 and the San Francisco Giants from 1993 to 2007. He is considered to be one of the greatest baseball players of all time.Recognized as an all-around player, Bonds received a record seven NL MVP awards and 12 Silver Slugger awards, along with 14 All-Star selections. He holds many MLB hitting records, including most career home runs (762), most home runs in a single season (73, set in 2001), and most career walks. Bonds led MLB in on-base plus slugging six times and placed within the top five hitters in 12 of his 17 qualifying seasons. For his defensive play in the outfield, he won eight Gold Glove awards. He also stole 514 bases, becoming the first and only MLB player to date with at least 500 home runs and 500 stolen bases. Bonds is ranked second in career Wins Above Replacement among all major league position players by both Fangraphs and Baseball-Reference.com, behind only Babe Ruth.Despite his accolades, Bonds led a controversial career, notably as a central figure in baseball's steroids scandal. He was indicted in 2007 on charges of perjury and obstruction of justice for allegedly lying to a grand jury during the federal government's investigation of BALCO, a manufacturer of an undetectable steroid. After the perjury charges were dropped, Bonds was convicted of obstruction of justice in 2011, but the conviction was overturned in 2015. During his ten years of eligibility, he did not receive the 75% of the vote needed to be elected to the National Baseball Hall of Fame. Some voters of the Baseball Writers' Association of America (BBWAA) stated that they did not vote for Bonds because they believe he used performance-enhancing drugs.