FOXBORO -- Maybe the clearest sign yet that Rodney Harrison's knee isn't slowing him down on the field is the fact that his gift of gab is in prime form these days.

Whenever he talks in the Patriots' locker room, Harrison is one of the team's best interviews. But this week, one of the NFL's top trash-talkers has been called out and yesterday he was more than ready to return the fire.

On Wednesday, Cincinnati Bengal receiver Chad Johnson told local reporters that "you can tell 37 (Harrison's number) I'll knock his helmet off."

The remark was said in jest and Harrison wore a wide smile yesterday when he loaded his guns for Johnson, who he considers a friend.

"He couldn't knock a mosquito's helmet off," Harrison said. "I used to really be bad back in the days in San Diego. I used to talk so much. But now Chad's taken over my lead and he's the king of trash talk. We'll see what happens on Sunday. I guarantee you, if he knocks my helmet off, I will retire."

Harrison kept rolling, defending Johnson's right to flap his gums just like he occasionally does. "The circus is in town," Harrison said. "He's a funny guy. This is the way he brings humor to the game and keeps himself energized. I know it's all in fun."

Other players cross the line, however. A prime example was Freddie Mitchell's below-the-belt shots at the Patriots before the Super Bowl two years ago.

"Chad is a baller and Freddie's not. Freddie's a bum. Chad's a baller," said Harrison. "It's all humorous. Look at the antics that go along with it. Chad's not looking to hurt anyone's feeling. He does it to motivate his team and maybe get a little spotlight for himself. But that's all good. That's what the NFL's about."

Just having Harrison back in the lineup is a blessing for the Patriots. In week three last season in Pittsburgh, the 13-year veteran suffered both a torn ACL and MCL in his knee. A long, difficult rehabilitation ensuend, but he stared down that challenge through the offseason and joined practice midway through training camp in August. He's started all three games this year, and while he may not be delivering the bone-jarring hits he's known for, he is the anchor the team sorely needs in its young secondary.

"I'm not 100 percent. I cannot be 100 percent off an injury like that," he said, "but that's no excuse. When I'm on the field, I'm on the field. I have to go out there and play and make tackles and knock the ball down and do what I do."

Harrison said that while his knee is strong, it's the mental side of the game that remains a challenge.

"Each week I'm gaining more confidence and feeling a lot better," he said. "I'm really starting to feel like I can do some things that I used to be able to do. It's not an easy injury to overcome but each week I feel like I'm getting better."

Watch for some extra attention to be paid to Harrison's knee injury this week if only because Cincinnati quarterback Carson Palmer suffered a knee injury a year ago and has made a full recovery. While Palmer's injury wasn't as severe, the timing was even more devastating to his team's success. He enjoyed a record-setting season in 2005, setting team records for TD passes (32) and completions (345) but when he went down on the second snap of a wild-card playoff game against Pittsburgh, the Bengals' season was over.

Patriots' coach Bill Belichick says that the ability of players like Harrison and Palmer to return from major knee injuries has dramatically changed the NFL.

"Those used to be 18 months, and then it was 15 months, and then it was a year. Now you have guys like Palmer coming back in, whatever it was, nine months, maybe even a little less than that," he said. "It's been remarkable. Then you have a lot of guys that are working hard like Carson, and like Rodney, guys like that who put a lot of extra time and effort into their rehabilitation. The body can only heal so fast, but certainly those guys have pushed it and the fact that they're out there as quickly as they have been is a real tribute to their hard work, and the people that are working with them."

Now that they're both back on the field, leading their teams, Harrison and Palmer can place the pain of injuries and rehabs out of their minds. Harrison is free to make big hits, track down Palmer's errant passes and match mouths like Chad Jackson word for word all afternoon.

kmcnamar@projo.com / (401) 277-7340