Leonhard made his major league debut on September 21, 1967, at the age of 26.[1] In three games with the 1967 Orioles, Leonhard went 0–0 with a 3.14 ERA in 14+1⁄3 innings of work.[1] In 1968, he finished with a 7–7 record in a starting rotation that included Dave McNally (22–10), Jim Hardin (18–13) and Tom Phoebus (15–15), but with the emergence of Jim Palmer in 1969, he was relegated to the bullpen.[1]
Leonhard appeared in the 1969 and 1971World Series (3.00 ERA in two games), and was a part of the team's roster in the 1970 World Series, though he did not make an appearance. After the series, the Orioles offered him a World Series ring or a TV; Leonhard picked the TV because he did not wear rings.[6] During the 1971 World Series, Weaver asked him to warm up during a game, a surprise to Leonhard because the Orioles had four 20-game winners on their staff. Weaver said it was "To scare 'em," to which Leonhard responded, "Earl, the Pirates have been scouting us just like we've been scouting them. They know better than to get scared by me." "Not the Pirates," Weaver responded. "I want to scare Palmer, McNally, and Cuellar into pitching better."[7] He played in his final major league game on September 20, 1972.[1] Leonhard continued to play in the minor leagues until he retired in 1976 at the age of 35.[3] He also pitched with the Puerto Rican team in the 1971 Caribbean Series and for Triple-A Salt Lake City Angels in 1973.[citation needed]
After he graduated from Johns Hopkins, Leonhard married Judy. She had been his girlfriend in high school, but they stopped dating initially when he went to college; however, their relationship started again when they saw each other at an alumni football game. They only stayed married for a few years before divorcing.[8] Palmer introduced him to Doris while the Orioles were visiting the Red Sox in the early 1970s, and she became his second wife. They opened a garden center in Beverly, Massachusetts, in 1975; as of 2010, they owned seven greenhouses in the area, where they sold plants and gardening materials.[8]
Leonhard was roommates with Palmer, who called him "my best friend on the team."[9] Palmer said, "Davey's education really was uncommon in the big leagues. He used words of more than one syllable, and he knew a pronoun was not a ex-amateur noun and stuff like that."[10] The Matz family lives behind Leonhards nursery in Beverly MA
