While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Comcast Corporation (NASDAQ:CMCSA) gained more than 2% today after Morgan Stanley upgraded the media and technology giant from equal weight to overweight.

So what: Along with the upgrade, analyst Benjamin Swinburne boosted his price target to $63, representing about 19% worth of upside to yesterday's close. While contrarian investors might be turned off by Comcast's solid share-price run in 2013, Swinburne thinks that Wall Street continues to underestimate its long-term growth prospects, giving the stock plenty more room to run.

Now what: According to Morgan Stanley, Comcast's risk/reward tradeoff is pretty attractive. "By investing in its product, brand, and network it has driven consistent 5-7% cable revenue and EBITDA growth and new initiatives like its next gen set-top platform and home security have yet to kick-in," Swinburne said in a report. "Finally, regardless of potential strategic activity in cable this year, we think the stock can outperform peers." With the stock now up about 45% from its 52-week lows, and trading at a 20-plus P/E, however, waiting for a wider margin of safety seems like the prudent move at this point. 

Fool contributor Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.