In 1977, Coventry loaned Green to the Washington Diplomats (Dips) of the North American Soccer League (NASL), whose season ran during the summer months, or the English off-season. Green played 16 games, scoring nine goals and assisting on five others. At the end of the 1978-79 English season, Green left Coventry to move permanently to the NASL, rejoining the Diplomats for the next two years. Green became a prolific scorer with the Dips, finding the net 42 times in 56 games, earning NASL All-Star Honorable Mention honours for 1980.