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 analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Key Energy Services, (NYSE:KEG) fell 2% today after Imperial Capital downgraded the oilfield services specialist from Outperform to In-Line.

So what: Along with the downgrade, analyst Scott Levine lowered his price target to $7.50 (from $10.50), representing just 7% worth of upside to Friday's close. So while contrarian traders might be attracted to Key's sharp pullback in recent weeks, Levine's call could reflect a sense on Wall Street that its growth prospects are just too limited to trigger a significant rebound.

Now what: According to Imperial, Key's risk/reward trade-off is pretty balanced at this point. "We believe KEG is well positioned to benefit from a recovery in U.S. onshore E&P activity, given its broad service portfolio and geographic footprint," said Levine. "That said, we think the upturn in several key U.S. production-driven markets could be somewhat slow to materialize, and while risk of further downside in the International segment is likely limited, a recovery in overseas earnings could take time to gain traction as well." When you couple that downbeat view with Key Energy's hefty debt load and highly volatile stock price, it's tough to disagree with Imperial's cautious stance.