NEW YORK (TheStreet) -- Henrique de Castro, the chief operating officer at Yahoo! (YHOO), is out, the company said late Wednesday. TheStreet's Brittany Umar said de Castro was the first big-name hire CEO Marissa Mayer brought in to Yahoo!, from Google  (GOOG), in late 2012

He was considered an important element to the core business of Yahoo!, where he was responsible for managing the company's sales, operations, media and business developments. This made his abrupt departure somewhat confounding to the financial and technology world, Umar said.

No reason was given for the firing but it was effective Thursday, according to a Securities and Exchange Commission filing, Umar said.

Display ad revenue fell in the third quarter, she added, leading some to wonder whether his performance was not at the level Mayer had expected. 

-- Written by Bret Kenwell in Petoskey, Mich.

Bret Kenwell currently writes, blogs and also contributes to Robert Weinstein's Weekly Options Newsletter. Focuses on short-to-intermediate-term trading opportunities that can be exposed via options. He prefers to use debit trades on momentum setups and credit trades on support/resistance setups. He also focuses on building long-term wealth by searching for consistent, quality dividend paying companies and long-term growth companies. He considers himself the surfer, not the wave, in relation to the market and himself. He has no allegiance to either the bull side or the bear side.

More from Opinion

Elon Musk's Latest Twitter Tirade Is the Dumbest Thing on Wall Street

Elon Musk's Latest Twitter Tirade Is the Dumbest Thing on Wall Street

Elon Musk's Twitter Tirade Is the Dumbest Thing on Wall Street

Elon Musk's Twitter Tirade Is the Dumbest Thing on Wall Street

Why Google's Search Momentum Won't Be Badly Hurt by New EU Rules

Why Google's Search Momentum Won't Be Badly Hurt by New EU Rules

Flashback Friday: Amazon, Chip Stocks, Memorial Day

Flashback Friday: Amazon, Chip Stocks, Memorial Day

Time to Talk Tesla: What Happened This Week, Elon?

Time to Talk Tesla: What Happened This Week, Elon?