10. Rosalind Chao As Tasha Yar
There was a lot of time spent on the casting of Tasha Yar during the preliminary period of Star Trek: The Next Generation. It was decided early on that they wanted the security chief to have an ethnicity and be a woman. Other than that, they weren't too specific. Quite how far Rosalind Chao got in the process isn't known, except for the statement of a memo of 13 April 1987. At the time the surname wasn't set, but the first name of Tasha was. So John Ferraro sent this to John Pike:
There are several contenders for 'Tasha', 'Geordi' and 'Data'. However, Rosalind Chao seems to be a favourite for 'Tasha'; Reggie Jackson for 'Geordi' and Mark Lindsay Chapman for 'Data'.
It just goes to show that auditioning early in the process doesn't mean that you'll get the part, as Star Trek fans will know none of those favourites got those roles. So what you might think happened is that Denise Crosby came in, auditioned and got the role. Not quite. You see, the only actress listed on that memo for Deanna Troi is Denise Crosby. Because at the time, they wanted the Tasha part to be ethnic, and the Troi part to be Caucasian. What actually happened is that Marina Sirtis came in and auditioned for Tasha and got the part, presumably displacing Chao. Then later on in the process, the producers decided to switch the parts for Crosby and Sirtis, resulting in the casting that would appear on the screen. It was only after Crosby was moved to the part of Tasha that the character gained her background and her surname. Chao may have had the last laugh over Crosby at least. She won the recurring part of Keiko Ishikawa, who married Chief Miles O'Brien and went on to appear in more episodes of the franchise than Crosby did as Tasha.