In the final stages of the Conference North game on Saturday - which the Blues won 2-0 - the 18-year-old County midfielder chased down Khan on the right touchline and clattered him with a late tackle.
The 29-year-old reacted by leaping up, picking up Russell and slamming him onto the turf, a move that saw him shown a red card.
Heeley told BBC Sport: "The football club in no way condones reactions like that, but [Khan] has had three or four career-threatening injuries from poor tackles. There's certainly a defence there.
"We've got to remember that incident wouldn't happen if the Stockport player didn't commit an awful challenge. There were a number of poorly-timed tackles that we were the victims of.
"Football's an emotional game. Shab is a lovely, mild-mannered lad and will feel he's let his teammates down. But there had been extreme provocation and we can certainly understand it."
The Pakistan international made his debut in 2004 for his hometown club but has made fewer than 200 appearances, having suffered a catalogue of long-term injuries during his career.