Boucher has spent this season with the AHL's Philadelphia Phantoms, but the former first-round draft pick has played in 220 NHL games for Philadelphia, Phoenix, Calgary, Chicago and Columbus. He is 23-16-1 this season with a 2.47 goals-against average, a .917 save percentage and four shutouts for the Phantoms.
The 31-year-old Boucher, who has played in 21 NHL playoff games, will join Thomas Greiss and Dimitri Patzold as the seldom-used backups to Nabokov, who has started all but two of the Sharks' 62 games this season. Both Greiss, who has the Sharks' only other two starts this season, and Patzold are rookies.
Nabokov platooned with Vesa Toskala over the past two years but has barely rested this season after Toskala was traded to Toronto.