In 1974, Washington was tapped by Oakland A's owner Charlie Finley to become the team's "designated runner". Finley and Washington worked out a one-year $45,000 contract with a $20,000 signing bonus. The contract had an unusual clause requiring Washington to grow facial hair before the beginning of the season. Washington had difficulty growing a full mustache, so he used an eyebrow pencil to simulate full facial hair.

Despite having no professional baseball experience, and having last played baseball in high school, Washington was a member of the Athletics 1974 World Series championship team. Finley announced that he would utilize Washington as a "designated runner" and that he did not expect Washington to develop other baseball skills. Washington received coaching on baserunning from Maury Wills. Though Washington's teammates recognized his speed, he received a mixed reception from them because of his unusual background. Reggie Jackson said, "He's a great athlete, but he's not a baseball player." Pitcher Rollie Fingers said that he thought the idea was "a little crazy" but that Washington "could run like crazy". Bert Campaneris said that the team could count on Washington to steal a base when needed.

Washington played in 105 MLB games without batting, pitching, or fielding, playing exclusively as a pinch runner. He had 31 stolen bases in 48 attempts and scored 33 runs during his short career. Washington is one of only seven players to have more game appearances than plate appearances, presumably excluding starting pitchers who played primarily for the American League, and relief pitchers.

Washington's 1975 Topps baseball card is the only baseball card ever released that uses the "pinch runner" position label.

October 4, 1972 would be last time a AL pitcher in a game would have to bat, and not removed from game

Nolan Ryan would be the last AL pitcher to bat before DH took effect next season.

Ryan would go 0-3 with 2 Ks while battling He struck out for third out in bottom of 7th vs Joe Horlen

Calif. would loose to Oakland 2-1
Ryan (19-16) pitched a complete game game loss

On April 6th, 1973 Ryan is entered into batting line-up becomes the 1st pitcher to be in line-up under DH rules when .....
In the Top of 9th ..
Nolan Ryan replaces Rudy Meoli (PR) pitching and batting 4th Tommy McCraw moves from DH to LF (team loses DH)