Warning! Spoilers about Greys Anatomy season 21, episode 1 ahead.

Dr. Sydney Heron appeared back in Grey's Anatomy season 2 before disappearing in season 4, but season 21 brought her back to Grey Sloan Memorial heres why the cheerful surgical resident left and what brought her back in Greys Anatomy season 21. Played by Kali Rocha, Sydney Heron greatly annoyed the original group of interns, Magic, due to her buoyant approach to everything that was thrown at them. The interns hesitation in dealing with Sydney was eventually shared by her fellow surgical residents, who often preferred to avoid working with her, highlighting how her positivity usually came out as passive-aggressive.

Greys Anatomys longevity as a TV show guaranteed the vast majority of characters left through the years. Becoming notorious for shockingly killing off its main characters, Greys Anatomy nonetheless let many of its characters leave the show without being dramatically killed. That was the case for...