Mid-day talker: Will the 49ers be fooled by Randy Moss?

The Great Chameleon, Randy Moss, is resurfacing in San Francisco. If you asked us to name a player who changes to fit his surroundings -- for better or worse -- and who also can influence his surroundings -- again, for better or worse -- more than Moss, we couldn't do it. When the Vikings were riding high, there was no better guy to have on the team than Moss. When seasons or games went sour, there was nobody worse.

Oakland? The Raiders were terrible, and Moss mailed it in.

New England? He was on an undefeated team and he was dynamic.

Back to the Vikings? The team was sinking and he was the final cannon blow.

Tennessee? It was a lost season for Moss, and he was a lost cause.

That was 2010. He didn't play at all in 2011. Now he's back for another shot, this time with the 49ers -- a squad that came within one game of the Super Bowl last year and can really use a dynamic playmaker.

So far? So good, SI.com reports. But, of course, it is early.

"In the classroom he sits in the front row, he soaks up the knowledge and always gives the feedback, too," Harbaugh said recently. "His attendance has been impeccable ... he's like a coach."

Safety Donte Whitner, who played against Moss in '07, when the receiver was having one of the alltime great seasons in history as a member of the Patriots, said, "He's running the same as he's always run. His body looks like a younger Randy Moss."

Moss reportedly has taken 49ers wide receiver Michael Crabtree under his wing. Another who is expected to be pushed by Moss, Kyle Williams, was enthusiastic about the veteran on Tuesday, when the 49ers gathered for an OTA.

"He's had a huge impact," Williams said. "He's a savvy vet. If you can't learn something from somebody like that, you're not paying attention."