[1] He was a left-handed pitcher in Major League Baseball from 1965 through 1979 for the Chicago Cubs, Oakland Athletics, Baltimore Orioles, and New York Yankees.

[7] After making three relief appearances in 1965, Holtzman joined the Cubs' starting rotation in 1966, and had an 11–16 rookie campaign as the team finished in last place.

The Cubs led the Eastern Division for much of the season before finishing in second place, eight games behind the eventual world champion New York Mets.

[2] In 1970, had a 17–11 record and a 3.38 ERA, and finished third in the NL in starts (38), fifth in both strikeouts (202) and innings pitched (287+2⁄3), sixth in complete games (15) and ninth in wins.

[15] On June 3, 1971, Holtzman pitched his second career no-hitter — the first ever at Riverfront Stadium — against the defending league champion Cincinnati Reds, winning the game, 1–0.

[16] Holtzman asked to be traded at the end of the 1971 season, so he was dealt to the Oakland Athletics in November in exchange for outfielder Rick Monday.

[10] Joining a staff that featured Vida Blue and Catfish Hunter, he won 19 games in 1972 (7th in the AL) and was named to the All-Star team for the first time.

[5] He lost Game 3 of the 1972 American League Championship Series against the Detroit Tigers as opposing pitcher Joe Coleman set an ALCS record with 14 strikeouts.

He relieved Hunter in the eighth inning of Game 7 with a 3–1 lead but after surrendering a double to Joe Morgan, he was replaced by Rollie Fingers.

In the 1973 ALCS against the Baltimore Orioles, he won an 11-inning 2–1 duel against Mike Cuellar in Game 3 when Bert Campaneris homered to lead off the last inning.

[1] Facing the Orioles in the 1974 ALCS, he pitched a 5–0 shutout in Game 2, taking a one-hitter into the eighth inning and allowing only five singles.

[19][20] After losing in salary arbitration in February,[21] Holtzman had an 18–14 record for the 1975 A's as they won their fifth straight American League Western Division title.

[24] With free agency imminent after the season and the expectations of higher salaries for which Athletics owner Finley was unwilling to pay, he was acquired along with Reggie Jackson and minor-league right-handed pitcher Bill Van Bommel by the Orioles for Don Baylor, Mike Torrez, and Paul Mitchell on April 2, 1976.

[25] When Jackson received a $60,000 raise to end his season-opening holdout, Holtzman accused Orioles general manager Hank Peters of a "double standard" for continuing to impose an automatic 20% pay cut on him and eight other unsigned teammates.

[26] A proposed trade that would've sent him and Bobby Grich to the Kansas City Royals but was dependent on him signing a contract failed to materialize on June 13.

[27] Holtzman was dealt along with Doyle Alexander, Elrod Hendricks, Grant Jackson, and Jimmy Freeman from the Orioles to the New York Yankees for Rick Dempsey, Scott McGregor, Tippy Martinez, Rudy May, and Dave Pagan just before the non-waiver trade deadline on June 15, 1976.