Randall has made just three starts since rejoining on loan after breaking a collarbone in September, which saw him return to Arsenal for treatment.
But boss Moore says the player is still adjusting to life at this level.
"He's not adjusted to League Two and that's why he's been on the bench but he's learning each day in training," he said.
"We're trying to do man-toman marking for him in training— he's learning his trade. It's nowhere near like at Arsenal when you're playing in League Two and people are closing you down—he's not been used to that.
"But he's still a quality player and if he can add that part to his game then he's still got a part to play for us this season."