The 22-year-old has developed the injury in his left foot, the problem discovered after the Tigers' eight-point win over Essendon in Wangaratta on Saturday evening.
Astbury, who has played just two senior games since dislocating his kneecap in round 12, 2011, had been enjoying a strong pre-season.
He had not missed a session – the first time he had achieved that since he was drafted in 2009 – and was praised by coach Damien Hardwick for his performance against Bomber forward Michael Hurley on the weekend.
Astbury said while he would miss the Tigers' clash with Hawthorn on Saturday plus the following week, he remained optimistic he would be selected for the senior team early in the season.
"Clearly the selection process for round one is heating up, and everyone will be doing their best to cement a spot in that team during the next few weeks," Astbury told The Age.
"It's very frustrating that I'll miss the opportunity to do that, but hopefully I'll still be considered and get an opportunity soon."
Hardwick said on Saturday that Astbury's game against Hurley was an important step in his development after he played the final two games of 2012.
"There's no doubt he helps us with his strong body," Hardwick said.
"He played on Hurley for the majority of the day and probably beat him, which was good.
"He's going to take a little bit of time given he did miss a significant amount of footy with that bad injury two years ago but he's only going to get better as the year progresses.
"He's still got to move the ball on a little bit faster at times, but we're really pleased with the way he's going."
The Tigers will have Nathan Foley (achilles) unavailable for round one and possibly Dylan Grimes, who is recovering from another hamstring operation.
Grimes joined the Tigers' main training group last week and is hoping to get some game time under his belt before round one.
He is expecting to available for selection around the March 28 season opener against Carlton but will need to play before then if he is to be considered.
David Astbury is a defender in NAB AFL Fantasy. He averaged 35 points in 2012. Register your team at our AFL Fantasy Hub.
Jennifer Phelan is a reporter for AFL Media. Follow her on Twitter @AFL_JenPhelan.
