Other players may also be involved, sources said.
San Francisco general manager Brian Sabean would not speak about any specific Molina trade scenarios during an interview on Wednesday, other than to acknowledge that he will consider trade offers for him.
The Giants are looking for left-handed hitting and are willing to move Molina as a way to get rookie Buster Posey in the lineup on a more regular basis.
Sabean said Wednesday that the team would prefer to add left-handed hitters who are under control beyond the end of this season. First baseman Chris Davis and catcher/first baseman Jarrod Saltalamacchia are among the Rangers who match that description; both are currently in the minor leagues.
However, one major-league source said neither Saltalamacchia nor Davis is involved in the proposed Molina deal.