The Nationals received second baseman Chris Bostick and right-handed reliever Abel De Los Santos, both minor leaguers.
The left-hander gets a fresh start in Texas and the Nationals get something back for his final year before free agency.
Also, more on interest in Ross Detwiler and the Nationals may trade a reliever before a starter.
The Astros have asked about Clippard; the Angels and Rangers were interested in Ross Detwiler; and other notes.
The Nationals tendered contracts to all of their arbitration-eligible players, including Ross Detwiler, Danny Espinosa and Jerry Blevins.
The Nationals have until midnight to tender contracts to 10 arbitration-eligible players.
The left-hander still views himself as a starter and it's unclear what the Nationals will do with him next season.
Scott Hairston and Ross Detwiler didn't make the roster, while Rafael Soriano and Jerry Blevins did.
Ross Detwiler has worked his way into a bigger role in the bullpen, even as his preference remains starting.
Ross Detwiler threw a splitter Wednesday night, two days after he tried it for the very first time.