Suzuki, 28, is likely to replace Jesus Flores as the Nationals' starting catcher.
"He's a No. 1 catcher," said manager Davey Johnson, who managed Suzuki five years ago during qualifying for the 2008 Olympics. "I liked his catching skills and I liked his bat potential then. And that was (five) years ago. He's done a good job in Oakland. He's a good catch-and-throw guy. Good hitter."
Suzuki is expected to report to the Nationals tomorrow. He's having a rough season offensively, batting a career-low .218 with one homer and 18 RBIs in 75 games. However, he is a .254 career hitter with 134 doubles, 57 home runs, 302 RBI and a .689 OPS in 703 games spanning six seasons (2007-present) with Oakland.
He's making $5 million this season, is owed $6.45 million for 2013 and also has an $8.5 million option for 2014 with a $650,000 buyout. The option vests if he makes 113 starts in 2013.
Suzuki leads all qualified American League catchers in fielding percentage (.996), caught stealings (23) and caught-stealing percentage (38.3) this season.
Flores has done a nice job handling the Nationals' pitching staff this season, but he's batting just .225 with three home runs and 18 RBIs and has thrown out only four of 47 runners attempting to steal (nine percent).
"Flo's still having some problems," Johnson said. "He's not back to where he was two years ago. ... He's not doing the things he knows he's really capable of doing."
Johnson said that current backup catcher Sandy Leon, who will catch the night game of today's doubleheader, is the "logical" option to be sent down to make room for Suzuki on the 25-man roster.
Freitas, 23, was the Nationals' 15th-round pick in 2010. He was hitting .271 with Single-A Potomac and was highly thought of within the Nationals organization.
Update: In order to clear a spot for Suzuki on the 40-man roster, the Nats designated catcher Carlos Maldonado for assignment.
Maldonado appeared in four games with the Nats this season, going 0-for-9 with an RBI. He hit .223 in 40 games for Triple-A Syracuse.