When a company's stock seems cheap, there's usually a reason. Often, it's because the company isn't a good investment: It may have been outpaced by competitors, loaded down with debt, or burdened by poor management decisions.

Generally, it's best to avoid those stocks. But sometimes, those underdogs are actually good companies that have hit rough patches. If management is up to the task of a turnaround, those stocks can be good buys. Here are three underdog stocks that our Foolish contributors are watching now: Under Armour (UA -1.03%)Gilead Sciences (GILD -0.01%), and Ford Motor Company (F 4.16%)

This underdog could rebound

Keith Noonan (Under Armour): Over the last year, Under Armour has gone from stock market darling to one of the S&P 500 index's biggest losers, but it's a company that I think still has big potential, and I'm keeping an eye on its stock with an interest in initiating a position.

^SPX Chart

^SPX data by YCharts.

While I do see potential for a rebound, it's undeniable that the apparel-maker's growth story has taken some unflattering turns. Sales growth has slowed substantially (last quarter actually saw domestic sales slip 1% year over year), and key product releases including the Curry 3 sneaker have failed to meet expectations -- casting doubt over the brand's ability to move upmarket and take advantage of premium pricing. Disappointing guidance and signs that the brand's appeal might be softening have also left analysts wondering whether the company's best days are behind it. 

An Under Armour cleat.

Image source: Under Armour.

So, there are sensible reasons to be down on the company and its stock, but here's why I'm interested. Under Armour currently generates only around 20% of its revenues from international markets, and overseas sales are still growing at a rapid clip with lots of room to run. This dynamic is especially true in large markets like China, where tailwinds like increased interest in basketball and football and an expanding middle class could mean big things for the company. Under Armour also has opportunities in connected fitness and expanding women's apparel sales, but it's the long-term international growth potential that makes it a stock to watch.    

From top dog to underdog

Keith Speights (Gilead Sciences): It wasn't all that long ago that Gilead Sciences was the darling of biotech investors. The company dominated the HIV marketplace with megablockbuster drugs like Atripla and Truvada. Gilead also blew up the hepatitis C virus (HCV) market with the first drug to actually cure the dreaded disease -- Sovaldi.

That was then. Things are much different now. While Gilead still makes a lot of money (nearly $13.5 billion in profit last year), the biotech is no longer viewed as a darling by investors. Gilead is more of a dud these days.

Three scientists working in a lab.

Image source: Getty Images.

Curing HCV was great at first. However, the number of patients began to dwindle as the sickest patients took Sovaldi and its successor, Harvoni, and no longer needed treatment. Gilead also faced competition from rivals with drugs that also boasted high cure rates for HCV.

Gilead now finds itself at a major crossroads. Its HIV franchise continues to perform well, but HCV product sales are tanking. Although the biotech's pipeline includes several promising candidates, especially in the potentially lucrative market for treating non-alcoholic steatohepatitis (NASH), commercialization for most of the drugs remains a few years off -- assuming all goes well in clinical studies.

I'm watching Gilead Sciences closely to see what acquisition the big biotech will make since the company's executives have hinted at possibly pursuing a sizable deal. Many investors, including me, eagerly await to find out which biotech (or possibly biotechs) Gilead might pursue. Gilead has gone from top dog to underdog, but I suspect there's plenty of bark and bite left in the company. 

Can a new CEO recharge this former investor darling? 

John Rosevear (Ford Motor Company): Right now, the "underdog" stock that has my closest attention is one I've owned since 2009, Ford Motor Company. At one point, my investment in Ford was approaching nine-bagger status, but since mid-2014, Ford's shares have slumped in a big way.

F Chart

F data by YCharts

What happened? Let's put it this way: The charismatic leader of Ford's turnaround, CEO Alan Mulally, retired on June 30, 2014. The chart above begins the next day. 

To be fair, Mulally's hand-picked successor, Mark Fields, didn't do a bad job. Among other achievements, he delivered Ford's two most profitable years ever in 2015 and 2016. But investor confidence in Ford ebbed amid concerns that Fields wasn't moving as quickly to boost profits and embrace new technologies as some rivals (in particular, General Motors). Now, Ford's formerly high-flying stock is an underdog. 

A 2017 Ford F-350 Super Duty pickup.

Ford has been making big profits on big trucks and SUVs, but investors wanted to see more. Image source: Ford Motor Company.

Ford's board of directors finally responded to investor concerns last week, ushering Fields into an early retirement and appointing Jim Hackett to replace him. Hackett is a turnaround veteran (he was CEO of Steelcase for many years) known for building strong teams and inspiring employees with a clear vision -- two keys to the success that Mulally had while running Ford. Hackett is also known as a tech-savvy leader: Before becoming CEO, he was running Ford's future-tech subsidiary, Ford Smart Mobility LLC. 

Will Hackett be able to bring back some of Mulally's magic to lead Ford more aggressively into the tech-enabled shared-mobility future? I think there's a good chance that the answer is "yes," but that's what I'm watching to find out.