Speaking to Entertainment Weekly, Rhimes explained that Alex (Justin Chambers) will struggle to cope with the recent shootings on the show.
"There's a lot of bravado," she said. "He tells stories about how he almost got the shooter and how he's carrying this bullet around in his chest. He's covering all of that vulnerability he showed when he got shot with that [typical] Alex behaviour."
Rhimes added that Alex will start to behave differently towards Lexie (Chyler Leigh).
"He's kind of cold to Lexie," she said. "He talks about how easy it is to get laid now because all the women think he's a hero."
The new season of Grey's Anatomy premieres on September 23 on ABC.
> 'Grey's' Pompeo: 'Meredith is caretaker'