Jon Heyman of CBS Sports first reported the deal.
Escobar was traded to the A's from the Tampa Bay Rays over the weekend. Over 137 games with Tampa Bay last season, Escobar batted .258 with seven home runs and 39 RBI. The 32-year-old has also had stints with the Atlanta Braves and Toronto Blue Jays.
Escobar will likely play second base for the Nationals unless the team is unable to keep Ian Desmond, in which case the new acquisition would likely be deployed at short stop. Desmond is slated to be a free agent during the 2016 offseason.
Clippard has pitched eight years in the majors, seven of which have come with the Nationals. The two-time All-Star had a 7-4 record with a 2.18 ERA over 70.1 innings pitched in 2014.
Washington posted the best team ERA (3.04) in Major League Baseball last season. Oakland was third-best with a 3.22 ERA. The A's were also second in the majors in opponents' batting average (.233).
The Nationals won the NL East last season after finishing 96-66 but lost the NL Divisional Series to the San Francisco Giants in four games. The A's finished second in the AL West but lost the AL Wild Card playoff game to the Kansas City Royals.
- Stanley Kay