The midfielder is set to miss this weekend's home meeting with Sunderland but that is about all Adkins could offer on the problem.
"Adam is still in his knee brace," he said. "He is progressing well and is now off the crutches.
"He won't be available for Saturday's game against Sunderland and that is all I need to say."
When pressed for more information, Adkins said: "That is all we are going to say.
"We're just going to say he is out for the Sunderland game and you can ask me the next question ahead of the next game."