 Elizabeth Reaser portrayed recurring character and love interest for Alex Karev, Rebecca "Ava" Pope, a patient suffering from amnesia after being involved in a massive ferry crash. Loretta Devine acted as Adele Webber, Richard's wife, whose continuous struggle to have a normal marriage culminates in her asking her husband to retire. Other guest stars include Sarah Utterback in the role of nurse Olivia Harper, former love interest of both George O'Malley and Alex Karev, Kali Rocha portraying fifth-year resident Sydney Heron, who enters a competition against Miranda Bailey and Callie Torres for the position of Chief Resident, Roger Rees in the role of Colin Marlowe, a cardiothoracic surgeon and Cristina Yang's former professor and lover, Jeff Perry portraying Meredith Grey's father, Thatcher Grey, Mare Winningham in the role of Susan Grey, Embeth Davidtz playing Derek Shepherd's sister Nancy Shepherd, who is revealed to have slept with Mark Sloan, Tsai Chin in the role of Helen Yang Rubenstein, Cristina's mother, and Diahann Carroll portraying Jane Burke, Preston Burke's over-protective mother. Future Private Practice series regulars Amy Brenneman, Paul Adelstein, Tim Daly, Taye Diggs, Chris Lowell starred in the twenty-second and twenty-third episodes of the season, portraying Violet Turner, Cooper Freedman, Peter Wilder, Sam Bennett and William "Dell" Parker, respectively, in order to make the transition to the proposed spin-off.
