Masters returned to the majors for limited duty in 1937 and 1939 (appearing in a total of 6 games[1]) then went 8–10 in 1940 for the Wilmington Blue Rocks and Portland Beavers. Masters then returned to the NFL and played in 1942 for the Chicago Cardinals as a punter-quarterback and in 1943 with the Card-Pitt. Overall, he did not excel in the NFL, averaging a loss of .6 yards per carry, completing under a third of his passes and throwing five times as many interceptions as touchdowns.
After six years out of organized baseball, Masters pitched for the Ottawa Nationals and went 11–4 with a 3.22 ERA and won both ends of a doubleheader. Masters finished his baseball career at the age of 40 in that 1947 campaign.
After retirement, Masters did public relations work for a company in Ottawa, Ontario.