The talented tight end isn't apologizing for being the antagonist.

"If I see things are quiet and the guys aren't getting rowdy," he said Wednesday, "I'm going to take it upon myself to do something about it."

Last year, Davis might have had a hard time finding defenders who were willing to engage in his psychological warfare. This year, however, there are several who seem more than happy to oblige.

During mini-camps, OTA's and training camp, the muscular tight end has gone face mask-to-face mask with linebacker Manny Lawson, who is noticeably bulkier and more confident in his second season. Free-agent additions Nate Clements and Michael Lewis haven't shied away from Davis, either.

And on Wednesday, Davis found that linebacker Tully Banta-Cain was up to the challenge, too. Following a pass play in which Davis burst into the secondary, Banta-Cain ran up from behind and tried to poke the ball free. A few seconds later, the two were bumping chests.

Far from despising the brash second-year player, 49ers defensive players said they enjoy the motivation.

"Vernon — he's a great player," Banta-Cain said after practice. "He really makes practice ... I don't want to say enjoyable, but he really keeps the energy level up."

Said Clements: "Vernon's a competitor — he backs it up. You can't be mad at that. He doesn't back down, and I wouldn't want him to back down from anyone."

Coach Mike Nolan likes what he sees, too.

The dominating Baltimore Ravens defenses he coached before arriving in San Francisco weren't shy about talking either, and middle linebacker Ray Lewis, an eight-time Pro Bowler, was typically the lead rabble rouser. Nolan believes the 49ers must have a similar swagger if, as they expect, they make their first playoff appearance since the 2002 season.

"As long as you can back it up, it doesn't bother me a lick," Nolan said. "... They just have to be smart about when and where they do it."

It's a warning Davis sometimes failed to heed last season.

Nolan cautioned Davis in the 2006 preseason when, following his first NFL touchdown catch in Dallas, he spiked the ball and raised both arms to the heavens, a la former 49ers and current Cowboys receiver Terrell Owens.

Davis also committed a nearly catastrophic penalty in Seattle last December when his end-zone celebration involved placing his foot on the pylon — a no-no in the NFL rulebook. The 49ers were clinging to a three-point lead at the time and the penalty cost them 15 yards on the following kickoff.

Davis said he's learned from those incidents but believes his enthusiasm is needed on the practice field.

After all, the 49ers' receiving corps is a mostly quiet bunch. So is the offensive line. Running back Frank Gore doesn't say much and neither does Smith.

So it's up to Davis to add spice when training camp seems too bland, to give it a pulse when it grows lifeless. And if he becomes the player the defense loves to hate? Well, that's precisely the point.