Manly Sea Eagles star fullback Tom Trbojevic has been ruled out of this weekend's Round 9 clash against the Gold Coast Titans.

Trbojevic left the field late in the contest last Sunday against the Wests Tigers, with the Sea Eagles managing to record a narrow win in Campbelltown.

The fullback has often not looked 100 per cent fit this year, and the club have now ruled him out of Saturday evening's clash with the Titans, revealing scans on Monday morning revealed a minor adductor injury.

Named at the back on Wednesday morning when teams were released for Round 9, speculation has followed that the fullback would be unable to take his place in the game, to be played at Brookvale.

The club have confirmed it was during a final fitness test at the captain's run on Friday morning when Trbojevic was ruled out, labelling the decision a "conservative approach."

The club expect him to return in Round 10 for a magic round blockbuster against the high-flying Brisbane Broncos.

In his place for this weekend's game against the Gold Coast Titans, Kaeo Weekes, who has served as both a utility and in the halves this season, will take the fullback role.

That comes with Josh Schuster also missing out on the first-choice spine at Manly, with Cooper Johns to once again partner Daly Cherry-Evans in the halves.

Weekes was originally named in the reserves for Manly this weekend, so his inclusion in the team will be a straight swap for Trbojevic.

The game kicks off at 5:30pm (AEST) on Saturday evening.