According to Evan Grant, the two teams from Texas are going after Phillies' ace, Cole Hamels.
The Rangers currently have a record of 43-49, and don't appear to be buyers on the surface, but Hamels represents a long term upgrade that any team that expects to contend in the next few years would want. It's possible that acquiring Hamels could help jump start a quickly fading Rangers team, but it's more likely that he'd be seen as a move to shore up the rotation for 2016 and beyond.
Grant notes that the Rangers would undoubtedly have to give up a top prospect in any deal for Hamels, and that Joey Gallo could be the headliner of any hypothetical trade. He also lists outfielder Nomar Mazara, or catcher Jorge Alfaro as potential pieces that could be moved.
As for the Astros, their name being connected to Hamels is somewhat of a surprise, as it seemed that they had been ruled out as a suitor for the prized left-hander earlier this year.
It's unclear what may have changed, if anything, but for the Astros to still be brought up in connection to Hamels would suggest that he would be willing to accept a deal to Houston. It would be a waste of everyone's time and effort to go about scouting players and engaging in trade talks if he would ultimately veto a trade to the Astros. The trade deadline is rapidly approaching, and with no major trades this month, the final days could be incredibly hectic.