Why do some dancers rise in a ballet company while others become stuck?

At American Ballet Theater, Melanie Hamrick seemed to be on the path to becoming a leading ballerina. A gracious, willowy dancer, Ms. Hamrick’s combination of line, warmth and a rare kind of transcendent beauty — it always reminded me of Julie Kent, a former Ballet Theater star — made her the kind of dancer y ou’d want to see as Juliet, say, or Giselle.

Early on, Ms. Hamrick, who started studying ballet as a child in Williamsburg, Va., danced prominent roles in “Apollo” and “Les Sylphides,” but gradually her debuts started to peter out. Ms. Hamrick said that Victor Barbee, the company’s former associate artistic director, used to tell her, “‘You’re just the best corps dancer we’ve ever had.’

“I was like, is that a good thing or a bad thing?” she continued. “Is that holding me back?”

Now after 15 years as a member of the corps de ballet, Ms. Hamrick has decided this fall season will be her final one with Ballet Theater. Her final performances — in “Apollo” last Sunday afternoon and as a demi-soloist in “Theme and Variations” on Tuesday and Saturday — are in ballets by George Balanchine. It’s fitting: As a dancer, she is sleek, musical and in possession of a great jump. “I love the feeling of ‘Apollo,’” she said. “It feels like coming home. It feels natural.”

One afternoon, before Ballet Theater’s fall season at Lincoln Center, Ms. Hamrick showed how true that was as she prepared in the studio for Calliope, a role she has danced before in “Apollo.”