The Mountaineers are at it again. Just a couple weeks ago, news that Starbucks (Nasdaq: SBUX) would begin selling a Verismo single-serve coffee brewer sent shares of Green Mountain Coffee Roasters (Nasdaq: GMCR) over the cliff -- down 16% in a day.

Fast-forward two weeks, and these same shares are bouncing right back.

Yesterday, Starbucks announced that, far from grinding Green Mountain into coffee dust, it actually wants to expand its relationship. Starbucks-branded coffee "pods" will now be available for use in Green Mountain's new Vue coffeemaker. Green Mountain shares rose 10%.

So is it time to climb the Mountain again?

In a word: "No." Green Mountain bulls have been pooh-poohing the Starbucks threat since last March, when the companies became BFFs in a deal to sell Starbucks pods for use in Green Mountain's original Keurig brewers. Everyone knew that Green Mountain's patents on the single-serve system were close to expiration and that Starbucks could develop a competing system.

But Starbucks' willingness to partner with Green Mountain, and its insistence that the Verismo is really an espresso maker, and not a competing coffeemaker, seemed to suggest the threat would never materialize.

It will. In fact, it already has.

The bull argument for Green Mountain hinges on two things: a reasonable stock price, and a breakneck rate of growth. As regards to price, Green Mountain looks pricey at 29-times trailing earnings, but you can argue that its 15 times forward P/E ratio is "reasonable." The average P/E on the Dow Jones Industrial Average (INDEX: ^DJI), after all, is nearly 13, and Green Mountain is growing much faster than average.

But that's just the thing -- Green Mountain must grow fast to justify its above-market P/E. The problem is that even if Starbucks doesn't target "coffeemakers" in particular, its entry into the single-serve, home-brewing game with an espresso maker cannot help but take away some potential Green Mountain sales. It calls the company's projected 33% long-term profits growth rate into question.

It's also worth considering how much Green Mountain's "profits" are really worth. The company claims to have been profitable (under GAAP) since way back in 1999. But Green Mountain hasn't generated a red cent's worth of real free cash flow since 2007. Instead, it's burned through more than $466 million in negative FCF (half of that in the past year alone).

Illusory profits and a vanishing growth rate do not a good buy thesis make.

Motley Fool contributor Rich Smith holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool owns shares of Starbucks. Motley Fool newsletter services have recommended buying shares of Green Mountain Coffee Roasters and Starbucks. Motley Fool newsletter services have recommended creating a lurking gator position in Green Mountain Coffee Roasters and writing covered calls on Starbucks.