The Arizona Diamondbacks are seriously discussing a trade of Justin Upton to the Atlanta Braves on Wednesday night, according to sources.

A deal to the Braves would unite Upton with his older brother, B.J. Upton, who signed as a free agent with Atlanta this winter.

The Diamondbacks want to decide whether to trade Justin Upton after more than a year of dangling the young star outfielder, or Jason Kubel sometime in the next 48 hours. Arizona has been discussing a possible Kubel deal with Baltimore, and sources involved in the Upton talks said Atlanta has made a strong offer that is likely built around pitching.

In any Upton deal, the Braves probably would surrender a package of prospects that won't include young shortstop Andrelton Simmons, a player Arizona asked for earlier in this offseason, sources said.

B.J. was excited about the possibility of a family reunion in the Braves' outfield.

"Wow these (at)JUS10UP10 rumors have me excited. Please don't tease me like this... Would be a dream come true if it happens," B.J. said on his Twitter account Wednesday.

The Diamondbacks once viewed Upton as a player they would build around for years to come. At age 21, he hit 26 homers, scored 84 runs and drove in 86 runs. In March 2010, Arizona signed Upton to a six-year, $51.5 million deal. It made the playoffs in 2011, and Upton finished fourth in the NL MVP voting.

But the Diamondbacks started discussing possible Upton trades that fall, and after he got off to a poor start in 2012, Arizona owner Ken Kendrick criticized Upton and other players in a radio interview.

"I think Justin is an enigma at this point," he told KTAR. "I know he had an injury early on and maybe a little bit of a nagging injury. But he's played. He's certainly not the Justin Upton that he has been in the past and that we would expect of him. He's 24 years old and it's time for him to be a consistent performer, and right now this year he's not been that."

Arizona again looked into trading Upton before the July 31 deadline last summer and continued to have discussions once this offseason began. It has become increasingly apparent that the relationship between the Diamondbacks and Upton has been damaged, perhaps beyond repair. Upton may well welcome a deal at this point.

Texas has seemed like a possible fit, and it traded proposals with Arizona that involved three and four teams, but the Diamondbacks asked for one of two young Rangers shortstops, Elvis Andrus or Jurickson Profar. The Rangers rejected that trade demand, then backed off more recently, sources said, knowing that David Price, Giancarlo Stanton and others might become available in the next year.

The Diamondbacks agreed to a proposed deal with Seattle earlier this month, but the Mariners are among four teams to which Upton could reject a trade, and he turned down the deal to Seattle.

Atlanta has emerged as a trade partner this week, feeling that Upton would be a good fit for its open spot in left field, and perhaps could be helped by playing alongside B.J.

Earlier this offseason, Atlanta, frustrated in its effort to sign Michael Bourn, worked out a five-year, $75.25 million with B.J. Upton to be its center fielder.

B.J. is 3 years old than Justin, and they have remained close through their respective careers.

Information from The Associated Press was used in this report.