Billionaire investor Carl Icahn inserted his two cents into the rumored exclusive negotiations between AOL and Google. Icahn warned that if the deal with the search engine would prevent a merger or deal with another online company, the board could be "on the verge of making a disastrous decision."

Icahn has already called for a shareholder vote to replace the Time Warner board, saying the company needs to streamline its business and begin setting up sales of assets that were holding the company's stock price down.

To back up his argument, Icahn cited a Goldman Sachs report that said Google was not the best partner for AOL financially, and that eBay or InterActive Corp. would provide better value. But the firm also said that a MSN deal would not provide much of an advantage over a partnership with Google.

"On the eve of a proxy contest, I believe it would be a blatant breach of fiduciary duty to enter into an agreement with Google that would either foreclose the possibility of entering into a transaction that would be more beneficial for Time Warner shareholders or make such a transaction more difficult to achieve," Icahn wrote.

Icahn said that if the rumors were true that Time Warner had only accepted bids from those looking to take a financial interest in the company, its actions would be "even more questionable." Time Warner would be taking too great a risk, Icahn says, and and an exclusive deal could prevent the company from maximizing AOL's value.

There is not an opposition to a partnership, Icahn added, only to one that takes away AOL's flexibility to work with other Internet companies. "I want this letter to serve as notice to Time Warner's directors that if they enter into a transaction that has that effect, shareholders will seek to hold directors responsible," he said.

The board of Time Warner is expected to meet on Wednesday, and an announcement on a possible Google-AOL deal has been rumored to come as early as Thursday.