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 Nike (NKE 1.55%) gained slightly on Wednesday after Morgan Stanley upgraded the sneaker giant from equal weight, to overweight.

So what: Along with the upgrade, analyst Jay Sole planted a price target of $85 on the stock, representing about 12% worth of upside to yesterday's close. While contrarian investors might be turned off by the stock's steady climb in 2013, Sole believes that there's some decent room to run given his view that Nike is on the cusp of solid EPS growth acceleration.

Now what: Morgan Stanley thinks the stock can deliver an annual 10% return over the next three years. "Nike dominates the industry and we think it's at a tipping point of major EPS growth acceleration sustaining a 17% 4-year EPS CAGR," noted Morgan Stanley. "Nike's powerful balance sheet is helping it create a virtuous circle of outsized investment spending, operational excellence, brand strength, and ROIC gains." With the stock hitting a new 52-week high today and trading at a P/E premium to its long-term average, however, I'd wait for a wider margin of safety in case Nike doesn't grow as quickly as Morgan Stanley expects.