Cablevision (CVC) shares tumbled and suffered several downgrades from analysts Friday morning, a day after announcing the surprise resignation of its chief operating officer, Tom Rutledge.

The resignation by Rutledge, 58, sparked speculation on Wall Street that he would be scooped up by a larger Cablevision competitor, such as Charter Communications (CHTR).

Cablevision, whose shares were down more than 14% to $11.93 on Friday, says it has started a search for an executive to oversee its cable business, which has more than 3 million subscribers.

Analysts at ISI Group cut the company to ‘hold’ from ‘buy’ late on Thursday, describing the departure by Rutledge as one of “the biggest bombshells in recent industry history,” according to Reuters.

Bernstein Research analyst Craig Moffett told Reuters that it was “a devastating loss for Cablevision.”

Rutledge, a nine-year veteran of Cablevision, has been highly regarded for his role in helping the New York cable operator steer clear of competition from Verizon (VZ) and satellite TV.

“Tom Rutledge has played a key role in driving and shaping Cablevision’s success over the last decade, applying a rare combination of technological vision and operational excellence that has delivered results,” said James Dolan, Cablevision’s chief executive.

He seems to be leaving at a time when he is needed most by the company, whose shares are down about 25% since August. In the most recent quarter, Cablevision reported a profit that missed Wall Street forecasts on a slowdown in subscriber growth.

Follow Jennifer Booton on Twitter at @Jbooton