In 1952, he went 11–8 with a 2.88 ERA (ninth in the league), as Washington improved to a 78–76 record. The following year he went 8–7 with a 3.03 ERA. In 1954 he was the oldest player in the major leagues, as he slipped to 3–6 with a 4.75 ERA. On January 24, 1955, the 43-year-old Marrero was released by the Senators.
