Ropati is expected to be sidelined for 12 weeks after with the Kiwi Test star also set to miss New Zealand's end of year tour to England. The 22-year-old injured his left shoulder making a tackle on Manly prop Glenn Hall in the opening minute of Sunday's victory at Mt Smart Stadium.
Hall has been cleared of serious damage and told he can return to the field in 2-3 weeks.
Still on the northern beaches, and Manly captain Matt Orford says he is confident the club's back-to-back losses are only a minor hiccup ahead of the finals.
The Sea Eagles have lost to South Sydney and New Zealand Warriors in successive weeks but have a chance to get winning form on the board when they host St George Illawarra at Brookvale on Sunday.
Orford says Manly must rediscover their discipline against the Dragons to gather momentum leading into the finals. He says Manly have suffered from poor discipline and uncharacteristic errors in recent weeks, but both can be easily rectified before the semi-finals.
The 23-year-old Webster has been released by the Gold Coast Titans and will play his final game against former club Melbourne at Olympic Park on Sunday. The Titans have revealed where Webster is headed but admit the damaging back has received a huge offer from an English Super League club.
The 29-year-old Gatis links with Huddersfield next season after signing a two year deal.
Titans managing director Michael Searle says Webster cited a chance to play in the centres as another big lure to head for the UK.