After those moves, and adding shortstop Gift Ngoepe on Thursday, the Pirates have 32 players on their 40-man roster, plus Jung Ho Kang on the 60-day disabled list.
Lambo, 27, made his Major League debut with the Pirates in 2013 and played 59 games with the Bucs in parts of three seasons. He made the Opening Day roster this year and recorded only one hit in 27 plate appearances.
Lambo last played on May 3, sitting out the rest of the season due to plantar fasciitis in his left foot. He is currently playing winter ball with the Gigantes del Cibao in the Dominican Republic.