Yahoo CEO Marissa Mayer called the recent firing of the company's chief operating officer "regrettable" during a fourth quarter earnings call on Tuesday, but added that Henrique de Castro was "not a fit."
Mayer also said that de Castro's position would not be filled, providing her with an opportunity to become more involved with Yahoo's revenue.
The comments came during the question and answer period of the call. Yahoo had earlier reported profits that beat analyst expectations, but shares moved between 3% and 6% lower in afterhours trading. Yahoo touted traffic growth and a rise in total ads sold to distract from a decline in revenue in the fourth quarter of 2013.
The earnings report comes at a sensitive time for the tech media giant. Mayer let go of de Castro earlier in January. Jai Sing, Yahoo's editor-in-chief, was not far behind.
The recent personnel turnover has called into question Mayer's turnaround efforts, although investors have been optimistic. Yahoo stock trades 142% higher than when Mayer first took the top job.
Yahoo's 24% stake in Chinese internet commerce site Alibaba is credited for the bulk of that increase, although the strong growth from that business appears to be slowing. Alibaba is likely to go public this year, in which case Yahoo's stake will be reduced to 14%.
As Joshua Brustein of Businessweek recently noted, Alibaba accounts for a large chunk of Yahoo's overall worth.