Per Ben Badler on Twitter, the Rangers are promoting Myrtle Beach shortstop Luis Sardinas and Myrtle Beach second baseman Rougned Odor to AA Frisco.
Sardinas, who turned 20 in May, was signed as part of the same J-2 class as Jurickson Profar, and was more highly regarded by some folks at the time. Injuries had curtailed his progress until this season, and he's put up a .298/.358/.359 line for high-A Myrtle Beach. He's considered by some to be the Rangers' top minor league prospect, as a very good defensive shortstop who is holding his own offensively in a league where he's one of the younger players.
Odor, 19, is hitting .306/.370/.457 for Myrtle Beach, and garners praise for his defense at second base and his solid offensive approach. He's also considered one of the Rangers' top prospects.
20 year old Hanser Alberto and 21 year old Odubel Herrera have gotten the bulk of the starts at shortstop and second base, respectively, for Frisco, and it is unclear whether they are going down to Myrtle Beach, or will be staying put. They have both struggled offensively this season, and probably would have been at Myrtle Beach this season were it not for the presence of Sardinas and Odor there.