"It's not quite ready," said Napoli, who has been on the disabled list since Aug. 11.
The Rangers were hoping that Napoli could be activated by Saturday, when the rosters expand to as many as 40 players. But they still want him to get at-bats on a rehab assignment before he is activated.
Triple-A Round Rock's season ends Monday. Double A Frisco's regular season also ends that day, but the RoughRiders are in the playoffs.