The Sabres also dealt backup goalie Martin Biron to the Philadelphia Flyers for a second-round pick. Buffalo then acquired Columbus Blue Jackets' backup goalie Ty Conklin for a fifth-round pick in this year's draft.
In the deal for Zubrus, a consistent offensive forward, Buffalo also landed prospect defenceman Timo Helbling. The Sabres dealt rookie forward Jiri Novotny, who's ready to return from a high ankle sprain, and a first-round pick to the Capitals.
Novotny, Buffalo's first-round pick in the 2001 draft, was enjoying a solid first full NHL season. He had six goals and seven assists for 13 points in 50 games. Novotny had missed the past three games after aggravating an ankle injury.
The Sabres completed the day by trading a fourth-round draft pick to Nashville for minor league defenceman Mikko Lehtonen.
The moves came as the Eastern Conference-leading Sabres prepare for their playoff run by bolstering an injury-depleted lineup that's missing eight regulars, including Tim Connolly, who had sat out the entire season following a concussion.
Zubrus was the key acquisition for Buffalo. A 10-year NHL veteran, he's third among Capitals scorers with 20 goals and 52 points - five short of matching a career high set last season - in 60 games.
Buffalo, which began the day at the US$44-million NHL salary cap, freed up room to acquire Zubrus by dealing Biron, who had been seeking a trade since losing the No. 1 job to Ryan Miller early last season.
Biron, who is making $2.1 million this season, proved expendable because he is in the final year of his contract and eligible to become an unrestricted free agent this summer.
Conklin was an inexpensive pickup as he is earning $525,000 this season.
Acquiring Biron gives the NHL-worst Flyers three goalies after the team kept Robert Esche, who was rumoured to be on the trade block. The Flyers also claimed forward Denis Hamel off waivers from Atlanta.
Starting goalie Antero Niittymaki has nine wins in 47 games, while Esche - once considered the future in goal after a stellar post-season three years ago - has played in only 18 games. Esche can be an unrestricted free agent at the end of the season.
"This is an opportunity for us to acquire a goaltender that we really like," Flyers general manager Paul Holmgren said. Noting that Biron would have been on the team's shopping list this summer, Holmgren added: "Trading for him gives us a chance to get a little more familiar with him and he can get a little more familiar with our team."
This was the second trade in two days for the Flyers, who acquired defenceman Lasse Kukkonen and a third-round pick from Chicago for forward Kyle Calder on Monday night. Calder was then traded to Detroit.
Buffalo's first-round pick in the 1995 draft, Biron is the Sabres' longest-serving player.
He has a 12-4-1 record and 3.04 goals-against average this season. His career record is 134-115-25 with four overtime or shootout losses, a 2.53 goals-against average and 18 shutouts.
Biron struggled in his last outing, allowing four goals before being pulled in the second period in a 6-5 loss at Ottawa on Saturday.
Conklin is a five-year veteran and career backup who was playing in his first season with Columbus. He has a 2-3-2 record with a 3.30 goals-against average in 11 appearances.
He spent the previous four seasons with Edmonton, his best year coming in 2003-04 when he went 17-14-4 with a 2.42 goals-against average with the Oilers.
In making the move, Columbus also announced that it had acquired goalie Brian Boucher off waivers from the Chicago Blackhawks.
Lehtonen, Nashville's ninth-round pick in the 2001 draft, had a goal and two assists in 15 games in making his NHL debut this season. He was currently playing with AHL Milwaukee and is expected to join Rochester, Buffalo's minor league affiliate.