Goldman Sachs’ Brantley Thompson this morning cut his rating on Tellabs (TLAB) to Sell from Neutral, asserting that the shares “fully discount the sales and margin improvement that we believe management will deliver.”

He says the call is relative to other communications equipment stocks he covers, and that he is “not calling for significant absolute downside.”

That said, Thompson asserts that expectations built into the stock price “already reflect a ramp in new products and a healthy second half.” He also writes that the low margin nature of many of the company’s new products will limit upside to margins; and he predicts that traction for the new products will be “slower than expected.”

He maintains an $11 price target on the stock.

Tellabs today is off 32 cents at $10.65.