"Chicago P.D." is getting new full-time members for their Intelligence Unit: fan favorite Antonio (Jon Seda) is making a comeback, while Erin Lindsay (Sophia Bush)'s departure means Hailey Upton (Tracy Spiridakos) is set to stay for good on the team.

After staying away for one season to work on the now-cancelled show spinoff "Chicago Justice," Antonio is back on the show. Only this time, he's going to be with a different team, especially after Erin's acceptance of a position with the New York FBI.

Talking with TVLine, Seda said that while he's going to miss working with co-star Sophia Bush, both he and his character will just have to keep going.

"It's hard. Antonio misses her. But he has to come back and do his job as best he can," he said. "Maybe they will have scenes where she's calling and talking on the phone or something. I don't know. Like I said, you really don't have time to stop and think about it. You've just got to move on."

Seda also confirmed that Antonio will be coming back as a detective. The Chicago P.D. team will encounter a situation where they will need outside help, Seda said, and when they bring in someone else to join the case, it will turn out to be Antonio joining in on the job. This will lead to Antonio coming back for good.

Meanwhile, Upton may have a romance on the line as she gets a permanent position on the team.

Showrunner Rick Eid told TV Guide that not only will she be facing interesting cases to solve and moral dilemmas to deal with, she will also probably be involved in a romantic story line.

Just who will Upton be falling for this season? "It will be somebody within our unit," Eid said, without revealing any further details.

"Chicago P.D." season 5 premieres on Sunday, Sept. 27, at 10 p.m. EDT on NBC.