NBC’s “Chicago P.D.” is known to surprise its fans from time to time. Last season’s explosive finale saw Hank Voight murder his son Justin’s killer. Season 4 will see several new actors – both recurring and guest stars – join the drama series. A new casting news may indicate that the show has just added a killer … or maybe an innocent witness on the show.

“Zoo” actor Billy Burke, who is known for taking up quirky roles on TV, has been cast as a legendary retired baseball player in “Chicago P.D.” Season 4, TVLine has learned. Even though it is a guest role, it doesn’t mean Burke’s character is insignificant. Speculation suggests he may either me an innocent witness or even a cold-blooded killer. Whatever his storyline may be, the “Revolution” alum will be playing an important role.

Burke will make his first appearance as a former baseball player in Season 4, episode 6, titled “Skin In The Game.” The 49-year-old actor has starred in several crime series, most recently he made appearances in TNT’s “Rizzoli & Isles” and “Major Crimes.” Movie fans may remember him as Bella’s father in the Twilight film series.

Apart from Burke, “Chicago P.D.” will also have another new character which will be introduced in the Season 4 premiere. “Quantico” and “Minority Report” actress Li Jun Li will play Julie Tay, Kim Burgess’ (Marina Squerciati) new patrol partner in the upcoming season on the NBC series.

Furthermore, apart from Lindsay (Sophia Bush) and Halstead’s (Jesse Lee Soffer) budding romance, “Chicago P.D.” will also show an affair between Antonio Dawson (Jon Seda) and “Chicago Fire” character Sylvie Brett (Kara Kilmer). The unlikely pair will hit it off in the Season 5 premiere of “Chicago Fire” when Antonio’s informant gets injured, TVLine reports.

While they may seem like an unlikely couple on the surface, the executive producer of both shows, Matt Olmstead, explained that fans will warm up to them eventually, “The things that initially would make you think that they should not date are things that we actually leaned into, that made sense, even though he’s older, divorced [and has] two kids. She’s looking for a real man, and he’s looking for a good woman,” he said.

“Chicago P.D.” Season 4 premieres on Wednesday, Sept. 21 at 10 p.m. EDT on NBC.

Billy Burke “Zoo” actor Billy Burke has landed a guest spot in “Chicago P.D.” Season 4. Pictured: Burke arrives at the CBS, CW, Showtime Summer TCA Party at Pacific Design Center on August 10 in West Hollywood. Photo: Getty Images/Matt Winkelmeyer