Tabaracci, 29, played with the Capitals before being traded to Calgary in 1995.
"Rick is a quality goalie who will provide depth and help create a strong tandem with Olie," Capitals general manager George McPhee said, referring to starting goalie Olaf Kolzig. "He is a former Capital who was excellent in the community so we expect an easy transition to Washington."
The 6-foot-1, 180-pound Tabaracci played a total of 46 games with the Capitals, spending part 1992-93 and all of 1994-95 in Washington.
A native of Toronto, Tabaracci played in 42 games with the Flames last season, posting a 13-22-6 record.