"I'm curious too," Giacomo Gianniotti told ET's Katie Krause of what DeLuca's mental state will be, while promoting My Friend's Place's five-day virtual festival, which closes with a gala Aug. 13. "I think it's going to be continued to be explored."
"That was a big build-up to the storyline that we ad talked about two years ago and it's slowly ramping up to this storyline for DeLuca," he said, alluding to his character genetically inheriting bipolar disorder from his surgeon father. "So I think where we ended, even though it's not exactly where we want it to end last season, there would have been a little more resolve [on DeLuca's part] had we not been shut down. We're going to have to play that this season."
With Richard Flood now a series regular, Gianniotti spoke about how Cormac "McWidow" Hayes' regular presence within the hospital walls will affect the love triangle among him, Meredith and DeLuca.
"In the beginning... I think it was clear he was having a hard time getting his foot in the door in that triangle," Gianniotti said of McWidow. "And by the end of it, because of DeLuca’s mental health, he really did not do any great favors for himself or for Meredith in terms of their relationship, leading Richard['s character] to be much more desirable and stable and more of a compatible partner."
"I think this season will feature a lot of DeLuca trying to make up for his wrongs, things he said, things he did 'cause he's unstable," he pondered. "And Meredith, trying to reconcile that or not, and Richard's character trying to continue to pursue Meredith. I think it's something that we still are interested in. We still want to play that; it's fun to watch. That's why they [promoted] him to series regular, so we could really have him around for a while and really tell that story -- and not have to tell it in a short time, but have a season or so to tell that."
As for whether Gianniotti's perspective has shifted on Meredith and DeLuca's long-term compatibility, he kept the door open on whether he believes they're endgame.
"They definitely have a great compatibility," he said. "I definitely think they have a lot of chemistry... I think of them as people who are opposites but you're attracted because of that. You sort of complement each other or fill each other's gaps in a way. They're yin and yang in the sense that they're in different places in their lives. They've had different experiences in their lives, and these are the things that complete each other. But I think that they have a good shot."
Gianniotti hopes there will be a time in the future when it's safe for him and cast members to venture outside of the studio lot for storylines or arcs set outside Grey Sloan.
"We work so much in our studio that I really envy actors that work on location a lot and go to different remote places. Jesse Williams, for example, had an episode where he was camping and a medical emergency arose in the wilderness and he didn’t have any of his equipment or tools. More stuff like that would be exciting -- on his day off or he’s on a vacation or somewhere where he’s unprepared for disaster to strike, and having to be creative in a moment of panic would be cool."
My Friend's Place Summer Festival five-day virtual gala closes with A Night United, hosted by Giacomo Gianniotti, on Thursday, Aug. 13.
To learn more about My Friend's Place and how to help, including with its COVID-19 Emergency Response Fund, visit myfriendsplace.org.
To stay up to date on breaking TV news, sign up for ET's daily newsletter.