Darden Restaurants Inc. said Thursday that it would sell or spin off its Red Lobster chain, which along with Olive Garden has been a drag on profits.

Orlando, Fla.-based Darden said it also would suspend the opening of new Olive Garden locations and limit new LongHorn Steakhouse restaurants.

Clarence Otis, Darden’s chairman and chief executive, acknowledged that the casual-dining segment was under pressure. He said the segment had experienced “relatively low levels of consumer demand in each of the past several years” and “additional unexpected softness since June.”

Activist investor Barington Capital Group, which holds about 2 percent of Darden’s shares, has been pressing Darden to split into two companies. The shareholder had called for one company to own and operate the mature Olive Garden and Red Lobster brands and another to manage the growing LongHorn Steakhouse, Bahama Breeze, Capital Grille, Eddie V’s, Seasons 52 and Yard House concepts. Darden’s plan keeps Olive Garden in the Darden fold.

Barington said a split could push Darden’s stock to between $71 and $80. Darden shares fell about 6.4 percent, to $49.53, in late morning trading Thursday.

The company has targeted the spinoff or sale of Red Lobster to be completed early in its fiscal 2015, which starts on May 26, 2014.

The move, Otis said, “will better enable the management teams of each company to focus their exclusive attention on their distinct value creation opportunities."

To accommodate the separation of Red Lobster, Darden also announced management changes. Kim Lopdrup, who now heads the Specialty Restaurant Group, will become chief executive of Red Lobster. He served as president of Red Lobster from 2004 to 2011.

Brad Richmond, now chief financial officer for Darden, will move to become CFO at Red Lobster, and the company will seek a new CFO to succeed him. Harald Herrmann, president of Yard House, will become president of the Specialty Restaurant Group in January.

Red Lobster has 705 restaurants in the United States and Canada and had fiscal 2013 sales of about $2.6 billion, but it has struggled amid a prolonged casual-dining downturn. The company said same-store sales for the brand fell 4.5 percent in September, 4.3 percent in October and 4.6 percent in November.

For the Nov. 24-ended second quarter, Darden reported a 41.1-percent decline in profit, to $19.6 million, or 15 cents per share, from $33.6 million, or 26 cents per share, in the prior-year period. Revenue rose 4.6 percent, to $2.05 billion from $1.96 billion in the same period last year.