Marv started 151 of 154 games at 2nd base for the Orioles as a rookie in 1960. He hit .269, but also committed 18 errors - 2nd on the team behind shortstop Ron Hansen's 29. The following season, Breeding shared the 2nd base job with rookie Jerry Adair, with Marv getting about 40% of the starts.
In 1962, Adair moved over to shortstop, but that didn't help Marv. Veteran Johnny Temple was acquired by the Orioles, and started 71 games at 2nd base to Marv's 56 starts. Breeding also appeared in another 40 games as a substitute and/or pinch-hitter.
After the season he was traded to the Senators, where he began the '63 season as the starting 2nd baseman. He soon lost his job to Chuck Cottier, and on June 30th was traded to the Dodgers for veteran pitcher Ed Roebuck. Marv finished out the '63 season with the Dodgers, but never played in the majors again.
He spent the 1964-68 seasons in the minors, playing for 8 organizations in 5 years, including a return to the Orioles' organization.
