Bob Nightengale of the USA Today cites two "high ranking club officials" (though he doesn't specify which club) as saying the Rangers are trying to land Atlanta Braves shortstop Andrelton Simmons, in order to then flip Simmons to the Arizona Diamondbacks in order to acquire rightfielder Justin Upton.
The D-Backs reportedly want a major league shortstop or third baseman for Upton, and the Rangers reportedly are refusing to part with either Elvis Andrus or Jurickson Profar in a deal for Upton. Acquiring Simmons would allow the Rangers to meet the D-Backs' asking price without parting with either Andrus or Profar.
I have no idea what the Rangers would have offered for Simmons, or what the Braves would have wanted.
Harold Reynolds said on the MLB Network earlier today that the Rangers were pursuing Braves shortstop Tyler Pastornicky, and while Reynolds seemed to suggest that such a move would allow the Rangers to deal both Andrus and Profar, it seems more likely that a Pastornicky acquisition would be, as with Simmons, in order to give the D-Backs a shortstop in an Upton deal.