The actress, who previously appeared on Law & Order, will portray Boston-based detective Jane Rizzoli, according to The Hollywood Reporter.
The potential programme is based on a number of mystery books by author Tess Gerritsen. The pilot episode has been written by Bones scribe Janet Tamaro, who will also serve as executive producer.
The adaptation is said to remain faithful to the novels, in which the titular character works on her cases with medical examiner Maura Isles. However, the latter role has not yet been cast.
Harmon, who also starred on short-lived ABC criminal procedural show Women's Murder Club, was called "a favourite of crime drama fans" by TNT programming head Michael Wright. He added: "She will bring a combination of toughness and sensitivity to the challenging lead role."
The 33-year-old is further scheduled to guest on the fourth episode of NBC's Chuck's new season, which begins in March 2010.