The barnstorming centre has been in something approaching career-best form this season for the Red V following his off-season switch from the Manly Sea Eagles.
While the Dragons have struggled to remain consistent, and currently sit two points out of the top eight, behind the Manly Sea Eagles (who they play on Friday night) and equal with the Sydney Roosters and Canberra Raiders, the club have lost two on the trot and let in 86 points over the last fortnight.
The club confirmed this evening that Suli has suffered a high-grade syndesmosis injury that will require surgery, ruling him out until the finals.
"Scans have confirmed Suli suffered a high grade syndesmosis injury," a club statement read.
"Additional consultations have determined the Tongan international will require syndesmosis stabilisation surgery which will keep him out until the finals."
Suli has been replaced for Friday's clash with Manly by utility Moses Mbye, which has brought Jayden Sullivan onto the bench, while Max Feagai sits in the reserves list after impressive form at NSW Cup level. Tyrell Sloan is also in the reserves and could be another option, although would have to play out of his preferred fullback position.
The 24-year-old centre has scored five tries and made a staggering 90 tackle breaks in his 17 games this season.
The game, to be played at Kogarah on Friday evening, is pivotal in the run to the finals, with it representing a four-point swing for the two clubs both battling for one of the final spots in the eight.