The Chevrolet Malibu, an also-ran in the popular midsize car segment, shows off a quick makeover Friday that is expected to address criticism of its bland styling and so-so performance.

General Motors will unveil the updates at a press event in Detroit. Experts are expecting to see a more modern-looking car, with some additional legroom in the back seat.

The rapid revamp comes just a year after the current version of the Malibu reached U.S. showrooms. But in midsize cars, the largest piece of the U.S. auto market, the Malibu looks old when compared with new versions of the Ford Fusion and Honda Accord. The gas mileage of the base model, an important selling point, also lags behind the top performers in the segment.

As a result, Malibu sales are down 12 percent through April, while Fusion sales are up 25 percent and Accord sales have risen more than 26 percent.

The Detroit automaker had to make the changes once it became clear that the Fusion, Accord and Nissan Altima were ahead in styling, performance or gas mileage, said Larry Dominique, a former Nissan product planning chief who now is executive vice president of the TrueCar.com auto pricing website.

"It's too important of a segment not to be competitive," Dominique said.

So far this year, Chevrolet has sold about 71,000 Malibus. But Ford has sold over 107,000 Fusions and Americans have bought almost 122,000 Accords.

Normally, automakers wait about three years for updates, with complete redesigns taking place every five or six years. But faster revamps are becoming necessary because of tough competition in many segments of the U.S. market. Toyota, for instance, delayed the launch of a revamped Camry midsize sedan last year to make changes due to competition, Honda redid its Civic compact just 18 months after it came out, Dominique said.

By redoing the Malibu, GM likely will avoid heavy discounts on the car, which can cost millions of dollars, Dominique said. "If you don't do it now, you've got four more years of a big problem," he said.

GM previously lowered the Malibu's base price between $300 to $770, depending on the model, in an effort to spur sales. The move had limited success.

The base version of the Malibu, with an automatic transmission and a 2.5-liter four-cylinder engine, gets an estimated 26 miles per gallon in combined city and highway driving, a figure that was respectable for a midsize car just a few years ago. But the base Altima gets an estimated 31 mpg, while the Accord gets 30. GM said it wouldn't release gas mileage or other details of the revamped Malibu until Friday morning.

On the plus side, the makeover shows that GM is a more responsive company than the one that went into bankruptcy protection in 2009, Dominique said.

Years ago, GM would have kept its factories running without change while selling more to rental car companies and raising discounts, Dominique said.

"I think this is indicative of the new GM, to respond to market competitiveness and improve quickly," he said.