He was gone for a few months, but Brett Harriss is back.

Gabelli's analyst upgraded shares of Sirius XM Radio (Nasdaq: SIRI) yesterday, nearly sending the satellite radio provider to a new two-year high.

Harriss feels that the media darling has the pricing power to begin inching rates higher once its regulator-mandated primary rate freeze thaws out this summer. He also sees the company having the balance sheet flexibility to begin buying back shares by the latter half of next year.

To put this analyst move into its proper perspective, he downgraded the stock just five months ago.

"Sirius needs time to grow into its valuation," he said at the time.

The Shyamalan plot twist here is that shares of Sirius XM were at $1.55 at the time. They were at $1.78 before his upgraded popped the stock up to $1.84. Sirius XM didn't just grow into valuation: It outgrew it!

Will regulators sign off on Sirius XM's ability to increase its rates starting this summer? If so, will the media giant act right away?

Given Sirius XM's model of high fixed overhead and low variable costs, it's easy to see how even the slightest uptick in revenue per subscriber would result in material bottom-line improvement.

Harriss still feels that Liberty Capital (Nasdaq: LCAPA) is the best way to play Sirius XM. Liberty's 40% preferred share stake in Sirius XM is worth nearly $5 billion now -- accounting for the lion's share of Liberty's market cap that's just north of $6 billion.

Liberty's eclectic portfolio also includes the Atlanta Braves, a pair of television stations, and more than a dozen minority investments in prolific companies. Those stakes include 18% of Live Nation (NYSE: LYV), 2% of Sprint Nextel (NYSE: S), and 3% of Crown Media Holdings (Nasdaq: CRWN).

There would be meaty taxable and logistical implications if Liberty were to unload its chunky 40% slice of Sirius XM, but there is the spin-off route. Either way, Liberty offers a way to participate in Sirius XM's upside with some protection on the way down given its diversified portfolio.

Either way, welcome back to the bullish camp. It's largely been the place to be with Sirius XM over the past two years.

Will Sirius XM raise its rates later this year? Share your thoughts in the comment box below.

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Longtime Fool contributor Rick Munarriz is a subscriber to both Sirius and XM. He does not own shares in any of the stocks in this article. He is also a member of the Rule Breakers analytical team, seeking out the next great growth stock early in its defiance. The Fool has a disclosure policy.