Byram, sidelined since April with a hip injury, played his first full 90 minutes in a behind-closed-doors friendly against Sunderland at Thorp Arch this week.
McDermott refused to be drawn on when Byram is likely to return to senior action, but said the teenage left-back was "getting close".
"Sam played 90 minutes on Monday and played well," McDermott told the club's official website.
"We haven't put timeframes on his return yet, but he must be getting close, which is great news.
"When you talk about transfer deadline days, how much would it have cost to buy Sam Byram?
"He is one of ours and he is coming back into our squad."