Lang is the fourth big-name Captial to be traded this season as Washington attempts to cut salary. Steve Konowalchuk was sent to the Colorado Avalanche, Jaromir Jagr was traded to the New York Rangers, and Peter Bondra was dealt to the Ottawa Senators.
Fleischmann is one of the Western Hockey League's top scorers. Detroit's second-round pick in the 2002 NHL Entry Draft, he's scored 28 goals and 69 points in 53 games with the Moose Jaw Warriors this season.
The draft picks sent to Washington were Detroit's first-round pick in 2004 and fourth-round pick in 2006.
The Red Wings will be Lang's fifth NHL team. He spent time with the Boston Bruins and Los Angeles Kings before spending almost four seasons with the Pittsburgh Penguins and the last two seasons with Washington. In eleven NHL seasons, Lang has scored 173 goals and added 289 assists in 640 games.
Lang is tied for the lead in the NHL's scoring race with Martin St. Louis of the Tampa Bay Lightning. He has 74 points this season.