Light heavyweight champion Chad Dawson and super middleweight champion Andre Ward are both coming off the biggest wins of their careers, but instead of taking it easy, they are planning to fight each other in September in a match of two of the best fighters in the world.

Dan Goossen, Ward's promoter, and Gary Shaw, Dawson's promoter, are in negotiations with HBO, which wants the bout.

"We have two fighters in their primes, two lineal champions. I think it's a great fight. You just don't get it in our sport too often," Goossen told ESPN.com on Thursday. "Two champions facing one another allows the winner to go out there and continue his climb to superstardom. That's what this fight is about. We need more of this in boxing. In boxing we want the big fights and it's very seldom you can have two world champions willing to face each other in their primes."

Goossen and Shaw said they are still discussing the specific weight limit -- whether it will be for the super middleweight or light heavyweight title.

"Our intent is to have it for Andre's super middleweight championship," Goossen said. "I still have a few things to close up with Gary. Gary and I have had good conversations and we're moving in the direction to making this fight happen."

Shaw said the fight could be at a catch weight slightly above the 168-pound super middleweight limit for Dawson's 175-pound world title.

"Chad has never ducked anyone and I believe the fight will get made," Shaw told ESPN.com. "It's going to be a great fight, a very interesting matchup between the best American fighters in their divisions. We want it very much as we want to fight the best. Dawson has fought all the top fighters at 175 pounds -- Antonio Tarver (twice), Glen Johnson (twice), Bernard Hopkins (twice) and Adrian Diaconu -- and we have a score to settle with Jean Pascal." Pascal handed Dawson his lone defeat.

Goossen and Shaw are exploring sites. Goossen said there are "a few sites very interested in hosting the fight."

He said the two leading possibilities are Oracle Arena in Oakland, Calif., Ward's hometown, where he has been a draw in the few fights he has had there, and Atlantic City, N.J., where both fighters have scored significant victories. Goossen also mentioned Southern California as another possibility.

"Atlantic City just had a great turnout for Dawson-(Bernard) Hopkins and I believe we could get 19,000 at Oracle Arena," Goossen said. "So I am partial to Oakland."

In December in Atlantic City, Ward culminated his domination of the Super Six World Boxing Classic tournament by easily outpointing England's Carl Froch to become the lineal super middleweight champion while also unifying a pair of belts, although he was subsequently stripped of one of the titles for no apparent reason.

The fight with Dawson will be Ward's first since winning the tournament. His layoff was caused in part by a hand injury he suffered against Froch. But his wife is also due with a baby in June and Ward wants some time off to be with his family during her pregnancy and the birth, meaning September was the earliest he could return, taking into account the time needed to train.

Dawson (31-1, 17 KOs), 29, of New Haven, Conn., claimed the lineal light heavyweight title, and regained an alphabet belt, on April 28 in Atlantic City when he scored a decisive decision win against Hopkins in a rematch of their aborted two-round, no-decision in October.

After Ward (25-0, 13 KOs), 28, defeated Froch, he spoke about his willingness to move up to fight a top light heavyweight if the opportunity presented itself.

"I am ready to fight the best 168- and 175-pounders that are out there," Ward told ESPN.com in a recent interview. "At this point, a big fight at 175 is interesting to me. I don't want to go up just to go up. But for the right fight, for a big fight, I would go up. I'm willing to fight anyone at '68 or '75."

After Dawson dispatched 47-year-old Hopkins, he specifically named Ward as an opponent he said he would like to fight, adding that he was willing to drop to super middleweight for the challenge.

The fight is headed to HBO because Showtime, which had rights to Ward's next fight after he won the Super Six (bankrolled by Showtime), passed on its option. Showtime had hoped to match Ward with super middleweight titlist Lucian Bute, the top super middleweight not invited to participate in the tournament.

However, there were never serious talks about making the match and Bute instead took a fight with Froch, whom he meets May 26. Showtime, which has a contract with Bute, gave him an out to take the Froch fight on another network, and Epix picked up the rights to it.

"Ward-Dawson will be on HBO and we're looking forward to it," Goossen said. "It's kind of a homecoming in a lot of ways, including working with Ken (Hershman)."

Hershman was running Showtime Sports when he invited Ward to participate in the Super Six. He left Showtime late last year and took over rival HBO Sports in January. Also, Ward, coming off his Olympic gold medal victory in 2004, made his professional debut on HBO.

Goossen said the fight with Dawson, an unusual match of two lineal champions in different divisions, is coming at the right time in Ward's career.

"Unlike in the tournament, where we had everything lined up for the next challenge, we were looking for something that was big after the tournament," he said. "We were looking at the winner of Hopkins-Dawson. With Chad being the winner, we put our attention there.

"I know some people are surprised we are going for this fight, but in Andre's career we have done things that have surprised people from the beginning. In his 20th fight we put him in the tournament and out of the box he was facing (titleholder Mikkel) Kessler and people said, 'What are you, nuts?' We try to push the envelope and try to do things bigger than people anticipate."