If Frazier is added to the 40-man roster, he would get a one-year contract paying a $1.5 million salary while in the major leagues, as part of the agreement announced Friday.
Pittsburgh is in need of depth at both corner infield spots after trading first baseman Josh Bell to Washington in the offseason. Colin Moran will move from third base to first full-time, with Ke'Bryan Hayes projected to start at third.
The 35-year-old Frazier is a career .242 hitter with 218 home runs and 636 RBIs while playing for five teams, including Cincinnati, the New York Mets and the New York Yankees. Frazier split time with Texas and the Mets in 2020, hitting .236 with four home runs and 12 RBIs.
Frazier is expected to join the Pirates in time to be on the field for the first day of workouts for position players on Monday.