Justin Upton for Chase Headley?

The Arizona Diamondbacks and San Diego Padres have held on-and-off discussions about a trade involving those players since July, but the talks have failed to progress, according to major-league sources.

The Diamondbacks, however, continue to discuss Upton with other clubs, including the Texas Rangers and Seattle Mariners, sources say, while also considering offers for another of their outfielders, Jason Kubel.

The Rangers want to acquire Upton without giving up either shortstop Elvis Andrus or infielder Jurickson Profar. Their preference is to build a package around third baseman Mike Olt, and the team is willing to add a top pitching prospect and third quality piece to the package, sources say.

But the D-backs, sources say, believe they could make an even better deal for Upton with another club — possibly the Mariners, who are aggressively trying to add a power hitter.

The problem for the D-Backs in trading with the Mariners is that the M's are on Upton's four-team no-trade list, and sources say that he is not inclined to approve a deal to Seattle.

That, however, could change if the Mariners redirected some of the money they were willing to pay free agent Josh Hamilton toward an extension for Upton, who is signed for $38.5 million over the next three years.