The cast of Grey's Anatomy is saying farewell to McSteamy. As we previously reported, Eric Dane passed away on Thursday afternoon after a battle with the neurodegenerative disease, amyotrophic lateral sclerosis or ALS. He was 53. Following the devastating news, several of his former co-stars and crew members from Grey's Anatomy have taken to social media to pay tribute to the beloved actor, who played Dr. Mark Sloan for 145 episodes of the popular medical drama. Related: Florida Rapper Lil Poppa Dead At 25 Kevin McKidd, who is Dr.