Petty suggested during Sunday's RaceDay show on Fox Sports "Speed" that Hamlin should end his 2012 season and focus on healing his lower back that was injured during an early season crash at Auto Club Speedway in California.
He also said Hamlin suggested he was the face of Joe Gibbs Racing.
Hamlin first lashed out on Twitter against the son of Hall of Famer Richard Petty.
— Denny Hamlin (@dennyhamlin) August 4, 2013
He continued to take shots at Petty after hitting the wall to end his day early at Pocono Raceway.
"He's an analyst, but not a very informative one because he doesn't know anything,'' Hamlin said. "My beef with Kyle is he has a lot of opinions about a lot of drivers, but he never once talked to any of them. To be an analyst you've got to be in the trenches to find out the stories.''
Asked what Petty said that upset him, Hamlin said, "It's just saying I thought I was the face of JGR. What I really said was I was the face of [primary sponsor] FedEx and the No. 11 team.''
"I think I've earned that right,'' Hamlin continued. "I've won enough races and I got here on hard work and winning. I didn't get here like he got here.''
Turns out, Hamlin had every right to be upset. Petty admitted to The Associated Press on Monday he had misinterpreted previous statements made by Hamlin, and the opinion Petty presented pre-race about Hamlin was incorrect.
"If you are going to run your mouth, if you are going to dish it out, you gotta take it, and the bone of contention here is that Denny is 100 percent right,'' Petty said. "I can take it, I can say that I'm wrong and that I misinterpreted what Denny said.''
Petty got his start in racing in 1979 driving for the family business, Petty Enterprises. In 30 years he had eight wins before eventually moving into the booth as an analyst.
Petty recently said Cup rookie Danica Patrick wasn't a driver and never would be. That fired up Patrick and team owner Tony Stewart, who last week at Indianapolis said the comments were "way out of line and very inappropriate.''
On Sunday, Petty made the following comments about Hamlin:
"You can't compete with teams like Jimmie Johnson and those guys and sit out five or six weeks,'' he said. "I think since that time now, he's started to talk a lot. He's talked about being the face of Joe Gibbs Racing. I think he's got a little bit of the BK [Brad Keselowski] syndrome in him right now.
"He's not relevant to the sport right now as far as the Chase and what's going on in the Chase and winning the championship. He can win the next four or five races, but it's not going to change the championship this year, and it's not going to change the Chase. It is what it is and he needs to focus on next year, get his body back together and come back and have a shot at winning next year."
While he admits he wrong about Hamlin on Sunday, Petty does not apologize for voicing his opinions.
"Sometimes I find myself the lone dissenting voice in this sea of political correctness, and I don't think everything has to be politically correct. Facts are facts, and honestly, it's just my opinion," Petty told The Associated Press. "I don't think that any of us -- me, Kyle Petty, media, the drivers, NASCAR, track owners, we aren't all right all the time. We don't all live in a utopian society where everything is perfect. There are things that need to be examined, that need to be called out, and I seem to be the only one that says it. That's the only way I've always been.
"It's just my opinion. It's just my question. Its questions that have to be asked. Just as it's their job to go out and drive the race car and do what they do, it's not our job to ask if they went fishing or went to the Bahamas and just ask the fluff. It's our responsibility to inform the fan base.''
Hamlin came into Sunday's race 25th in the standings, 111 points outside the top 20 needed with a win to be eligible for a wild card spot in the Chase.
He will miss the Chase for the first time since coming into NASCAR's top series in 2006.
Hamlin said he and crew chief Darian Grubb are working on setups that will help them for next season.
"Lately, it's not been good,'' Hamlin said. "It's been a handful. We've been qualifying OK, but as soon as we get in traffic and the race starts we go dead backwards and loose.
"Just a very frustrating season. We're kind of outside of our normal box of setups and so we're trying to get better for next year, but obviously we need some track time to do that.''
Information from The Associated Press was used in this report.