In the midst of a struggle with Internet rival Google, Inc. (Nasdaq: GOOG), Yahoo Inc. (NASDAQ: YHOO) said Monday that the company’s co-founder Jerry Yang will replace Terry Semel, who is resigning as chief executive.

Shares of Yahoo slid slightly Tuesday morning to trade at $27.70, down 42 cents, or 1.5 percent. The stock began the day up more than 4 percent higher from its previous close after news of the management changes.

In the announcement, Yahoo said Semel will assume the position of non-executive chairman while co-founder Jerry Yang takes over day-to-day management as CEO. The company also announced Susan Decker, the head of Yahoo's advertiser and publisher group and ex-finance chief, has been named president.

Some experts lauded the move, believing that the company's current management hasn't done enough to fend off rivals, particularly Mountain View, Calif. Internet giant, Google Inc. (Nasdaq: GOOG), which commands search based advertising on the internet.

We believe Yahoo! has long-term structural challenges driven at the core by the emergence of Google and its high-margin natural monopoly search business, said Scott Devitt, analyst with Stifel Nicolaus.

Yahoo is also losing ground to social networks, community sites, traditional media as well as Google’s new content initiatives - iGoogle, Universal Search and Google Gears.

Yang , who founded the company more than 13 years ago with David Filo, is known more for his technical prowess than his managerial skills. In his role as Chief Yahoo”, he has played an active role with the current board.

Semel, a former executive at Hollywood studio Warner Bros., took charge of Yahoo six years ago when the company was struggling after a burst in the technology bubble. He is credited with rebuilding the firm's online advertising model and media businesses.

In recent years he has been criticized as Yahoo lost ground in search, advertising, and most recently, social networking platforms, such as MySpace and Facebook.

Recent departures of senior management, cries from within for leadership, disapproval with Semel's compensation has led to a decline in company morale, Rob Sanderson of American Technology Research explained to clients Tuesday.

While fundamentals are not great, we see management changes as a key step in recovery and find valuation attractive,” he said.