Miller signed a minor-league contract with the Padres on Tuesday that includes an invitation to spring training, AJ Cassavell of MLB.com reports.
The Rangers transferred Miller (hamstring) to the 60-day injured list Friday.
Miller (hamstring) will begin a rehab assignment Friday with Double-A Frisco.
Texas placed Miller on the 10-day injured list Wednesday with a left hamstring strain.
Miller started at designated hitter and went 2-for-3 with a walk, a double and two runs scored in Sunday's 8-4 win over the Dodgers.
Texas activated Miller (oblique) from the 10-day injured list Friday.
Miller (oblique) started at first base and went 0-for-2 with Triple-A Round Rock on Tuesday.
Miller (oblique) is beginning a rehab assignment Tuesday with Triple-A Round Rock.
Miller was placed on the 10-day injured list Saturday, retroactive to May 31, with a right oblique strain.
Miller served as the designated hitter and went 0-for-4 in Tuesday's 5-0 loss to Seattle.