Brinker International Inc.'s (EAT) July sales were weaker than initial company projections, as a new promotion at Chili's Grill & Bar drove down sales.

"We attribute this change to our tactical decisions to offer a new promotion at Chili's," Chief Executive Doug Brooks told investors on an earnings conference call Thursday.

Chili's latest promotion offers an appetizer, two entrees and dessert for $20, which is helping lift traffic, but not enough to make up for lower sales. Brooks said the deal has lower margins than other menu items, which will affect profits.

Brinker shares fell $2.35, of $12.8%, to $15.97 in recent trading, after the company reported fourth-quarter results and laid out earnings projections below Wall Street expectations.

-By Paul Ziobro, Dow Jones Newswires; 212-416-2194; paul.ziobro@dowjones.com