Grey’s Anatomy creator and executive-producer, Shonda Rhimes, gave interviews to Entertainment Weekly and TV Insider about what’s in store for season 13.
The interviews are rather extensive and so I haven’t posted them in their entirety, only the parts that relate to Justin and his character, Alex Karev. The full interviews can be read at the sources that are linked to below.

★ From Entertainment Weekly

ENTERTAINMENT WEEKLY: The show is putting focus back on the remaining original characters. How is that resonating in the stories in season 13?
SHONDA RHIMES: It just means that part of what we’re doing is we’re really telling stories that are about — our story arcs this season are about Meredith, about Alex, about Bailey, and about Richard, and that’s where we’re pointing our compass right now.

EW: Does season 13 therefore feel in the spirit of those early seasons?
My goal is always that every season feels like it’s its own special animal, so I don’t think that would be a totally accurate thing to say. But I think it does feel really good.

EW: Speaking of what’s next, in the finale, Alex beat DeLuca within an inch of his life. Can you talk about the consequences of his actions both legally and professionally?
There are going to be some really big consequences. We talked about it a lot in the writer’s room, how we were going to deal with this, and what we thought made sense, and I really wanted to tell a story that felt true. What happens when you really screw up? Alex is a guy who has worked really hard to grow up, and be a responsible adult, and to not be the kid he was when we first met him. To find himself in this position I think is just interesting for him as a character because he is in this place of growth. He is a character who every single time he has become involved with a woman, that woman has, in some way, destroyed him. We are going to watch what happens for him now and how that challenges him and changes him.

EW: Justin has intimated that we’re seeing an Alex that is more like the jerk of the earlier seasons.
I think people who are hurt revert to their less mature selves a lot of the time. He is hurt and he doesn’t quite know how to cope with that. What I love is that he and Meredith are trying to get through it together, and she’s trying to take care of him, and he’s trying to take care of her, and at times they don’t appreciate each other’s methods.

EW: How will what Alex did divide the hospital?
I’m not as keen on the concept that it’s going to divide the hospital. It definitely poses some problems for the people in charge. It definitely poses some problems for Bailey, who has worked really hard to be in charge and to find a place of leadership, then to find herself in a situation that is really volatile, and a very volatile workplace is not a lot of fun. The idea that one of her employees has attacked another one of her employees, what is she going to do and how is she going to cope? That world is really interesting to watch her survive in, especially when it’s supposed to be a teaching environment; it’s supposed to be a nurturing environment.
And I love the fact that we’re going to get to know DeLuca a lot better, who we don’t know at all, and who we’ve just started to scratch the surface of. Now, because this thing has happened to him, he has found himself in a spotlight that he was not interested in ever being in.

EW: How is what Alex did going to affect his relationship with Jo?
I think that is going to be the key. That relationship is going to be deeply affected — I don’t think that there’s any way it couldn’t be after what he did, after what happened. There’s no way to have that occur and to expect that there aren’t going to be any consequences.

EW: One of the more shocking moments at the end of the season is that Jo Wilson is not actually Jo Wilson. Where did this idea come from and what more are we actually going to learn about her this season?
Oddly enough, that concept is something that we — the writers — have talked about for years, and have always been like, “Is this the right time? Is this the right time?” We’ve been trying to figure out when to deploy that. It felt right at this moment in time because Jo’s backstory has always been very intriguing to us, and this idea that she is now fully who she says she is, and that she is somebody who has reinvented herself. I love her as being somebody who has reinvented herself. I also love her as being somebody who has overcome a lot of really, really bad things to make something of her life. She’s a survivor. The idea that she’s a survivor and that very act of being that person is threatening to that relationship is interesting. The fact that Alex is a guy who his response is to beat somebody up is a little problematic.

EW: You’re introducing a story of domestic violence this year with Jo’s past. How big will that feature and why was it important to showcase that this year?
I don‘t think that I ever think about doing things, like, “Oh, we’re doing a domestic violence story as an issue.” It felt like it was time to tell Jo’s story, and it felt like it was time to tell Jo’s story especially in the context of Alex, who he is and how he grew up. Alex is so defined by who he used to be and who he is trying to become, and so is Jo. So those stories were very interesting to me. Meredith suffered a violent attack last year and very much overcame it. This idea that women are often treated in this way is disturbing to me, but it’s also very interesting to me to get to tell the story of Jo from this perspective of somebody who has walked away from a past that happened so long ago, and might have to face it again.

★ From TV Insider

Is there life beyond McDreamy? Oh, hell yeah! Last season, Grey’s Anatomy followed Dr. Meredith Grey (Ellen Pompeo) as she grieved for her husband, Derek Shepherd (Patrick Dempsey). The ratings spiked, and Grey’s ended the 2015–16 season as the third highest-rated network drama in the advertiser-coveted 18–49 demo (behind Empire and The X-Files), a stunning achievement for a 12-year-old program that—by all the rules of showbiz—should require life support by now.

That said, the show’s creator, Shonda Rhimes, isn’t reveling in all this viewer love. On the eve of the show’s 13th season, she’s only thinking about one fan, and that fan’s name is Shonda Rhimes.

“Here’s how I operate: If I don’t completely reinvent Grey’s Anatomy every season, then I’m not going to be interested anymore,” Rhimes says. “I need to keep this show fresh and rewarding and moving forward. Last season was about Meredith trying to figure out who she is without her marriage and her best friend, Cristina [Sandra Oh]—in fact, without her whole support system.” Now, says Rhimes, “we find out what this rebuilding of Meredith’s life really means and how it affects the people around her, and we’re really going to test her ride-or-die friendship with Alex [Justin Chambers].”

In last May’s season finale, Alex beat the bejesus out of Andrew (Giacomo Gianniotti) after the doc thought he’d caught the young intern about to have sex with his girlfriend, Jo (Camilla Luddington). (In fact, Andrew had simply escorted a drunk Jo home and was helping her to bed.) Now Andrew is fighting for his life and Alex is the most hated man at Grey Sloan Memorial. “There’s just no way to spin it to make Alex look good,” Rhimes says.