In exchange, the Nationals sent infielder Steve Lombardozzi, left-hander Ian Krol and minor league lefty Robbie Ray to the Tigers.
Fister, 29, went 14-9 with a 3.67 ERA in 33 games last year in his third season with the Tigers. Fister was tied for the American League lead in getting batters to ground into double plays. He allowed 0.6 home runs per nine innings, second best in the AL.
Source: ESPN.com news services