Tom Lynch will undergo surgery after scans confirmed the star forward had suffered a fracture in his right foot.
Lynch suffered the injury in the second term of Richmond's loss to the Western Bulldogs on Saturday, benched for close to ten minutes in the aftermath before playing out the game.
Speaking post-game, Richmond coach Damien Hardwick conceded that Lynch might not be fit for Round 5, while the Tigers confirmed the news that Lynch would undergo surgery on Sunday.
The club also confirmed that a timeline for Lynch's return to the field will be assessed after surgery.
"Lynch sustained the injury during the second quarter of yesterday's match against the Western Bulldogs," the statement said.
"The Club will have a clearer indication of the injury's timeline following surgery."
Set to be sidelined for Round 5 anyway, Lynch is also facing MRO scrutiny for a bump in a marking contest against Bulldog Alex Keath, with the MRO findings to be released on Sunday evening.
Lynch has played all four games for Richmond this season, kicking nine goals.