Foley will join the show as Henry, a seriously ill patient whom Teddy (Kim Raver) is desperate to save.
Speaking to TV Guide, Foley acknowledged the parallels with the previous storyline involving Izzie and her patient Denny.
"Sure, there are some definite similarities there," he said. "The fact that something might happen between Henry and Teddy the way that it did between Denny and Izzie is a definite possibility. That was such a truly epic storyline and really one of the tent poles of the show. I could never dare to say that Henry would be anything like that."
Henry eventually persuades Teddy to take on his case pro bono, but Foley insisted that he is not a bad person.
"He needs someone to take his cause up, but I think he's just a nice guy," he said. "I think anybody who's sick and possibly terminally ill would do whatever they could to get better."
Grey's Anatomy continues on Thursdays at 9/8c on ABC.