'Chicago P.D.' season 4 spoilers, plot news: Are Lindsay and Halstead starting a family? Jesse Lee Soffer teases couple's future

The "Chicago P.D." season 4 premiere episode saw Detective Jay Halstead (Jesse Lee Soffer) very sweetly asking his girlfriend detective Erin Lindsay (Sophia Bush) to move in with him. But just how much further are they going to take their relationship in the police procedural drama's new season?

In an interview with E! News on the red carpet at NBC's Television Critics Association summer press tour, Soffer previewed the season 4 arc of the Lindsay-Halstead romance, saying that they will be "domesticating the relationship."

But just because both Lindsay and Halstead are keen on taking that huge step in their relationship doesn't mean that they will just go ahead and do so. According to the actor, there is one external — but major — factor to consider before the couple actually move in together: their boss and Lindsay's father figure, Voight (Jason Beghe).

"We'll see if Voight lets that happen," Soffer said. "Actually no, I think Voight's OK with that now, but we'll see."

"They might move in and they might start a family one day!" he teased. "Who knows?"

The "Chicago P.D." actor also hinted at how Lindsay's dilemma about Voight's crime will affect Halstead, explaining that his character will have to pick up the pieces after Lindsay gets involved with covering up for the murder Voight committed.

"The darkness might interfere," Soffer said.

Meanwhile, in an interview with Entertainment Weekly, executive producer Matt Olmstead talked about the new dynamic between Lindsay and Voight.

"There's always a debt that Lindsay feels towards Voight, but the student one day becomes the master and the master is proud the student is ascending," he explained. "There's always going to be some heartbreak there, because someone's leaving to go into the world, essentially, he added."

According to Olmstead, while it will be very complicated for Voight, he will nonetheless be proud of Lindsay and sympathetic about what she has to go through.

"Chicago P.D." season 4 airs Wednesdays at 10 p.m. EDT on NBC.