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 Medtronic (NYSE:MDT) climbed 1% today after Deutsche Bank upgraded the medical device giant from "hold" to "buy."

So what: Along with the upgrade, analyst Kristen Stewart boosted her price target to $66 (from $56), representing about 16% worth of upside to yesterday's close. While value investors might be turned off by the stock's big run in 2013, Stewart believes that there's room to run given several key catalysts that should help Medtronic improve its fundamentals even further.

Now what: Deutsche sees plenty of opportunities for P/E expansion and earnings upside over the long term.

"Over the past year, the company has improved its execution and has been delivering on its goals," noted Deutsche. "Medtronic is still largely a 'show me' story, but we believe over the next 9-12 months there will be several key catalysts that should increase investor confidence in the ability to accelerate top line and deliver sustained high single digit EPS growth."

With the stock up more than 30% year-to-date and trading at a 15-plus P/E, however, I'd wait for a wider margin of safety in case Medtronic doesn't grow as smoothly as Deutsche expects.

Fool contributor Brian Pacampara has no position in any stocks mentioned. The Motley Fool owns shares of Medtronic. 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.