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 Zimmer Holdings, (UNKNOWN:ZMH.DL) gained a small 1% yesterday after Cantor Fitzgerald upgraded the medical device giant from hold to buy.

So what: Along with the upgrade, analyst Jeremy Feffer boosted his price target to $105 (from $98), representing about 15% worth of upside to Thursday's close. So while momentum traders might be turned off by Zimmer's sharp pullback in recent weeks, Feffer's call could reflect a strengthening sense on Wall Street that its growth prospects are becoming too cheap to pass up.

Now what: According to Cantor, Zimmer represents a particularly timely opportunity. "We are upgrading Zimmer to BUY from HOLD and raising our price target to $105 from $98 as improving volume and mix trends have made the stock's deep discount to its orthopedic and large-cap medtech peer group increasingly inappropriate, in our view," said Feffer. "With the stock off ~7.5% since reaching a closing high on 3/10 (versus the S&P's -0.7%), we believe the stock's risk/reward profile is compelling, particularly ahead of its 1Q report that we expect to be in line." When you couple that short-term potential with Zimmer's still-attractive long-term qualities, it's tough to disagree with Cantor's upgrade. 

Brian Pacampara has no position in any 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 insightsmakes us better investors. The Motley Fool has a disclosure policy.