The Athletics sent Suzuki to the Nationals last August to help Washington with an injury-depleted catching core. Suzuki hit .267 in 43 games with the Nationals last season, but has struggled this year, batting .222/.283/.310 in 281 plate appearances.
Suzuki had seen his playing time diminish recently, appearing in only 16 games since Wilson Ramos returned from the disabled list. Ramos missed over 50 games this season with a left hamstring strain.
Oakland had been searching for catching help for the past two weeks, according to Susan Slusser of the San Francisco Chronicle. John Jaso is currently out with a concussion, and may be sidelined for the rest of the year. Suzuki is familiar with the pitching staff, and has performed better offensively in his career with Oakland than he has this season with Washington.
The Nationals will receive 22 year-old right-hander Dakota Bacus. Bacus has a 3.56 ERA over 121 1/3 innings in Single-A.