Gibcus suffered a hamstring injury back in January and was nearing a return before the suffering a strain in his right hamstring this week, with the club now to take a "cautious approach" with his return.
The 20-year-old is yet to play in 2023 after an 18-game debut season that saw the defender claim Richmond's Best First-Year Player award.
Richmond's high performance manager Luke Meehan confirmed the injury news on Friday.
“Josh was closely working towards a return to play before unfortunately injuring his hamstring on Thursday," Meehan said.
“It's not as significant as his injury in January, and is in a different spot, but given his young age and long future in the game, we will be taking a cautious approach with his recovery- prioritising the long term.
“We will get some rehab work into him over the coming weeks and be able to provide a further update from there.”