Yahoo’s Chief Operating Officer Henrique de Castro left the company Thursday, having been apparently fired. Yahoo announced the news in a US Security and Exchange Commission filing. It offered no reason for his departure but said it was effective immediately.

De Castro joined CEO Marissa Mayer as her first high profile appointment, just three months after her own in October 2012. Both previously worked at Google.

De Castro had been serving as VP of Google’s worldwide partner business solutions group, where he was responsible for advertising platforms and services for Google’s publisher and commerce partners. At Yahoo, he was tasked with managing sales, operations, media and business development worldwide.

“I’m personally excited to have him join Yahoo’s strong leadership team,” said Mayer at the time.

De Castro’s departure was rumoured as early as September last year. At the time, advertising news site Adweek cited sources close to the matter claiming that de Castro was under pressure to deliver better results and that various sources believed that he would be out of the firm by the end of 2013.

In 3Q13, the firm saw its quarterly GAAP revenue drop five per cent year on year to $1.14bn, its GAAP income from operations fell 39 per cent year on year to $93m. Net earnings fell 91 per cent from $3.16bn to $297m.