"Blue Bloods" will be getting an infusion of new blood when the series returns for a seventh season.

The Reagans will be facing new challenges in season 7 in the form of a lawyer determined to get to the truth of Thomas Wilder's death and a mother who wants to keep her son safe. Michael Imperioli and Lori Loughlin have been tapped to play them, respectively.

According to Entertainment Weekly, Loughlin has signed on to play Grace, a widow who pleads for help from Frank Reagan (Tom Selleck). The widow of a slain police officer, Grace reportedly doesn't want her son to join the police force and wants Frank to dissuade him.

Meanwhile, Imperioli will be playing Miller, a lawyer from the Attorney General's office who has been assigned to look into Danny Reagan (Donnie Wahlberg) and the death of Thomas Wilder (Louis Cancelmi), the serial killer.

Fans will recall that Wilder murdered several women, taunting Danny each time and even leaving one victim on the steps of Reagan's church. Danny and Wilder's dangerous game of cat and mouse came to a head in season 6's 20th episode. Titled "Down the Rabbit Hole," the episode saw Wilder kidnapping Nicky. Danny eventually catches Wilder in an open field and shot him.

The Attorney General looking into the Thomas Wilder case seems inevitable. The question now is how this will affect the Reagans and Danny's already shaky marriage to Linda (Amy Carlson). Fortunately, Frank will still be around to rally and lead his family.

Deadline has recently confirmed that Tom Selleck had signed a deal to reprise his role as Police Commissioner Frank Reagan. The character has long been known for his loyalty and dedication to his family and the police force, but fans will reportedly see a new side of the hardened law man. There have been reports that Frank will be getting a love interest in season 7, which some fans believe to be long overdue.

"Blue Bloods" season 7 will return to CBS on Sept. 23 at 10 p.m.