Astbury rolled his ankle following a nasty landing during Richmond's Anzac Day Eve victory over Melbourne, with the 10-day break not aiding his cause to prove his fitness.
"He probably won't play," Hardwick said.
"He won't train today (Thursday). It was an incredible effort to play
the size of his ankle, he was lucky to get his boot back on.
"We had a conversation before and he's looking increasingly unlikely at this stage. It probably means he's really doubtful for the weekend's game.
"He's an important player for us and we'll give him every chance but it's not looking likely at this stage."
Source: AFL website