Jurcina, 23, had two goals, one assist and 20 penalty minutes in 40 games with the Bruins this season, his second in the NHL. The 6-4, 245-pound Slovak had 11 points (6-5) in 51 games with the Bruins in his rookie season last year.
He's earning US$500,000 this season and will be a restricted free agent July 1.
"This acquisition is consistent with what we are trying to accomplish," Caps GM George McPhee said in a statement. "Milan Jurcina is a young guy with some growth potential. We expect that he will help our penalty kill right away and we look forward to seeing how else he can help us in the long term."