Fedotov agreed to terms on a two-year, $6.5 million contract extension with Philadelphia on Tuesday, Darren Dreger of TSN reports.
Fedotov stopped nine of 13 shots in a relief appearance during Tuesday's 9-3 loss to Montreal.
Fedotov made 15 saves in Friday's 4-2 loss to the Sabres.
Fedotov will patrol the visiting crease in Buffalo on Friday, according to Jordan Hall of NBC Sports Philadelphia.
Fedotov officially joined Philadelphia on Friday after his contract with CSKA Moscow was terminated.
The IIHF has determined that Fedotov was in breach of contract rules when he signed with CSKA Moscow of the KHL in July because he had a valid deal with Philadelphia.
Fedotov (illness) has dropped his appeal to the Russian government, which means he'll be compelled to serve a full year in the military and thus won't be an option for Philadelphia in 2022-23, source reports.