The 27-year-old, who was called up after Mike Napoli was placed on the 15-day disabled list with a strained left quad, is giving incumbent starting catcher Geovany Soto a day off.
Washington believes catching is one area where the Rangers could receive better production, as Napoli has had a down year after a career 2011 season and Soto has struggled, especially since coming to the American League.
In 11 games since joining the Rangers, Soto was batting just .175 with a .233 on-base percentage and a .275 slugging percentage.
As a whole, Texas catchers are hovering around the league average mark, which is .243/.310/.400.
Washington said it's a difficult position to pinch-hit for, so he will have to live with the production he is getting for now.
The problem with pinch-hitting for a catcher, according to Washington, is that if his replacement gets injured, it can be detrimental to the team because he would have to turn to someone inexperienced.
Getting Napoli back, who is hitting .223 with 17 homers and 40 RBIs, will be key.
That may not happen until September, as the club plans to take it slow with him, but Washington is encouraged by Napoli's progress.
"He's been doing a lot of squats out there with medicine balls trying to strengthen [the quad]," Washington said. "He looks different in batting practice, so his body must be feeling better. Not that he ever made that an excuse. He's working."