Pfeifer signed a minor-league contract with the Giants as a non-roster invitee Friday, Amy Gutierrez of the Giants' official site reports.
Pfeifer was outrighted to Triple-A Gwinnett on Friday.
Pfeifer was placed on the 45-day injured list with a bone contusion on his left elbow Tuesday, 680 The Fan Atlanta reports.
The Braves optioned Pfeifer to Triple-A Gwinnett on Wednesday.
Pfeifer's contract was selected by the Braves on Tuesday.
Pfeifer has received a non-roster invite to Atlanta's spring training.
Pfeifer was traded to the Braves on Thursday, Joel Sherman of the New York Post reports.