In May 1968, the Rangers signed a formal agreement with the Denver Broncos to act as a farm team of sorts for the AFL club.[3] Later in the year, football legend Ernie Nevers became a stockholder and member of the team's board, with the intent of helping the team become a member of the NFL or AFL.[4] Head coach Mel McCain was fired during the 1968–69 offseason.
Less than a year after attempting to purchase the Boston Patriots of the AFL, Rangers owner Lafa Lane announced his intention to sell a controlling interest in the Rangers.[5] Lane resigned as chairman and president of the team at the end of October 1969,[6] although the team did finish its season. With the end of the COFL in 1970, the Seattle Rangers also ceased operations although no official announcement was made.