In a world where there are 18 seasons of Grey's Anatomy, it's hard to imagine Derek Shepherd being portrayed by anyone but Patrick Dempsey, but that wasn't always going to be the case. In fact, the role of the charming neurosurgeon was actually first offered to Rob Lowe, who turned it down to star in the CBS show Dr. Vegas, which was cancelled after a month of airing.
For over a decade, Dempsey starred as Meredith Grey's love interest, often nicknamed "McDreamy," until his character's death in Season 11 Episode 21, "How To Save a Life." He then proceeded to guest star in Season 17 in a dream-sequence, as Meredith fights COVID-19. The fictional couple became world-renowned for their on-screen chemistry, and were named to numerous "Best Couples on Television" lists. For his work on Grey's Anatomy, Dempsey was nominated for a Golden Globe for Best Performance by an Actor in a Television Series Drama in 2006 and 2007, and the 2006 SAG Award for Outstanding Performance by an Actor in a Drama Series. Dempsey was undeniably critically acclaimed for his role, but what would have happened if Rob Lowe had taken his place?
The character of Derek Shepherd had his distinct qualities -- he was brilliant, he was enchanting, and he was a catapult for the drama on the show. His relationship with Meredith was the backbone of the first 11 seasons, dictating the emotional state of Meredith and even what field she would decide as her specialty when leaving residence. Derek was always meant to be an important part of the show, and the actor who played him had to convey that importance through his dramatization, and according to an interview with Variety, Lowe never felt he would've been right for the show. "If it'd been me (the fans) wouldn't have called me 'McDreamy,'" he said, "they would have called me Rob Lowe." Even though Lowe passed on the role to join a short-lived drama about a physician working in a casino, he has no regrets, and neither do Grey's fans.
Before Grey's Anatomy was even a concept, Rob Lowe had already established himself as an actor in the industry as a member of the Brat Pack in the 1980s, starring in prominent films as a teenager such as About Last Night... and The Outsiders. Almost a decade later, his career took a turn as he sought more television roles and became known for his work in The West Wing. Given Rob Lowe's star status at the time, him sticking around for 11 seasons on a borderline soap-opera medical drama was unlikely. The former teen idol is known for going from project to project, ranging from political dramas to mockumentary comedies. If Lowe had taken on the McDreamy role, Meredith Grey may have lost her husband many seasons earlier, and the show could've suffered tremendously because of it.
Looking at what Patrick Dempsey's career could've been without Grey's... it might have also suffered as much as the show. While Lowe had the recognition to support him declining ABC's medical drama, Dempsey wouldn't have been so lucky. He might have had several supporting roles in television series and a few major roles in films such as Sweet Home Alabama, but the actor became known for playing Derek Shepherd and actually received many roles outside of Grey's because of the increased attention the show brought. During and after Grey's, he made his mark in romantic comedy films, and even a Transformers movie.
While some fans may still be in interested in a "what-if" scenario where Rob Lowe plays the charismatic surgeon, there's no denying the character wouldn't be what it is without Patrick Dempsey. If it were the other way around, Lowe wouldn't have played the energetic and overly-positive Chris Traeger in Parks and Recreation, and Grey's Anatomy may not have lasted as long as it has.
New episodes of Grey's Anatomy premiere Thursdays at 9 PM ET on ABC and can be streamed the following day on Hulu.