#3 Robert Lang
Like Matt Niskanen, Robert Lang was also a pickup from the Pittsburgh Penguins. Lang was only around the Washington Capitals for two years. At the time of his signing which occurred on July 1, 2002, it was a five year deal but he was traded as part of that fire sale in the 2003-04 season.
Who did they get in the trade? A first round pick from the Detroit Red Wings in 2004 (which turned out to be Mike Green) as well as Tomas Fleishmann.
Lang scored 22 goals and had 47 assists for a nice 69 points in his first season with the Caps. He followed that up with 29 goals and 45 assists for 74 points in 63 games before he was traded to the Red Wings.
Lang was nearly a point per game player during his time in D.C. In 2003 he was playing 22 minutes a game and was the Caps main guy. In the playoffs against the Tampa Bay Lightning, Lang had three points in six games. That was his lone time the Capitals were in the playoffs with him on the team as they bowed out in the first round.
The reason someone that short of a term is ranked so high? The return the Caps got in the trade (which led to Mike Green).