Riley was placed on the minor-league disabled list due to a sprain of his posterior cruciate ligament in his right knee, David O'Brien of the Atlanta Journal-Constitution reports.
Riley is expected to miss a couple more weeks after suffering the injury diving for a groundball against Louisville on June 3. The third baseman is expected to join the Braves later on this summer, though this issue could complicate his arrival if he doesn't progress according to plan. Through 26 games for Gwinnett in 2018, Riley is hitting .284 with a .776 OPS.