Robertson signed with the Sugar Land Skeeters of the independent Atlantic League on Tuesday, Brandon Warne of ZoneCoverage.com reports.
Robertson signed a minor-league deal with the Diamondacks on Wednesday, Chris Cotillo of SB Nation reports.
The Indians designated Robertson for assignment Thursday.
Robertson was placed on the disabled list at Triple-A Columbus with left hamstring soreness.
Robertson was optioned to Triple-A Columbus on Monday.
Robertson will start in left field and bat ninth Sunday against the Twins, Jordan Bastian of MLB.com reports.
Robertson went 2-for-4 with his first major-league home run, a three-run shot, and scored twice in Tuesday's loss to the Dodgers.
Robertson will start in right field and lead off Sunday against the White Sox, Jordan Bastian of MLB.com reports.
Robertson went 2-for-5 with a double and three RBI in Sunday's 8-0 win over Kansas City.
Robertson will start in left field and bat second Sunday against the Royals, Paul Hoynes of Cleveland.com reports.