Tellabs (TLAB) shares are lower Friday morning after UBS analyst Nikos Theodosopolous cut his rating on the stock to Neutral from Buy. He also trimmed his price target on the stock to $6.50 from $8.

Theodosopoulos says he had upgraded his rating on the shares in January based on two catalysts: a recovery in U.S. wireless infrastructure spending and M&A potential. But he now has shifted his view on both fronts.

On the one hand, he says wireless pending is “ramping slower than expected” in the U.S. And on the other hand, he says an acquisition of the company now looks less likely in the near-term. Theodosopoulos notes that shares of potential buyers Nortel (NT) and Ericsson (ERIC) are both down sharply. He notes that Nortel and Tellabs now have comparable market caps; he thinks Ericsson may find Nortel to be a more strategic target.

Tellabs today is down 25 cents, or 4.4%, to $5.40.