The 28-year-old Suzuki was batting .218 with a home run and 18 RBIs for Oakland. Manager Davey Johnson said he expects Suzuki to report in time for Saturday's home game against the Miami Marlins.
In a strange twist, the A's traded Gio Gonzalez to the Nationals in December and received both lefty starting pitcher Tommy Milone and catcher-of-the-future Derek Norris. Now, Suzuki will get to catch the All-Star Gonzalez again, across the country in the NL.
Still, Oakland general manager Billy Beane said when Norris was promoted this spring it didn't necessarily mean Suzuki would be on the trading block. Everybody expected him to be gone soon, however.
"It's a chance for us to move forward with Derek and a chance for Zuk to play every day somewhere else," A's assistant general manager David Forst said.
Washington wanted to shore up its catching spot after the mid-May loss of Wilson Ramos with a torn ACL. Jesus Flores has been the starting catcher, though Johnson referred to Suzuki as "a No. 1 catcher."
When General Manager Mike Rizzo brought up Suzuki to Johnson, the manager enthusiastically endorsed the acquisition.
"I said, 'Man, that would definitely bolster our catching corps," said Johnson, who managed Suzuki in a 2006 U.S. Olympic qualifying tournament.
Oakland is picking up some of the salary owed Suzuki, who is signed for $5 million this year and $6.45 million next season. His contract includes an $8.5 million team option for 2014 with a $650,000 buyout.
"He's in the Gold Glove conversation each and every year," Rizzo said. "He's not a rental. He's going to be here for more than this season."
Flores had surgery on his right shoulder in September 2009 and missed the following season. He's batting .225 with three home runs and 18 RBIs and has has thrown out just five of the 48 runners attempting to steal. Suzuki has thrown out 38 percent of runners this season.
"Flo is still having some problems. He's not back to where he was," Johnson said.
Freitas was batting .271 for Class-A Potomac.