Both players were restricted free agents. Financial terms were not released. Eminger had one goal and 16 assists in 68 games last season. The 23-year-old has six goals and 35 assists in 192 career games with the Capitals.
The six-foot-two, 217-pound Toronto native was Washington's first pick (12th overall) in the 2002 NHL entry draft.
Sutherby, 25, had seven goals and 10 assists last season. He has 25 goals and 35 assists in 254 career games with Washington.
The Edmonton native was also a first-round selection by the Capitals. He was taken 26th overall in the 2000 draft.