Since he was last in the NRL, Ben Barba has had a brief spell in rugby union with Toulon and in Super League with St Helens.
Widnes Vikings were sent down to the second tier with a 20-12 loss to Toronto Wolfpack, while St Helens eased to victory over Warrington.
Victory over Hull FC clinched St Helens the League Leaders' Shield as Dom Manfredi inspired Wigan on his return to action.
Super League will revert to a more conventional 'one up, one down' promotion and relegation system in the 2019 season.
Just as St Helens' Super 8s frustrations looked set to continue, Morgan Knowles came to the rescue at Catalans Dragons on Saturday.
St Helens were made to wait to lift the Super League leaders' shield after a humbling 30-10 defeat against bitter rivals Wigan Warriors.
After two defeats in a row, St Helens moved a step closer to claiming the League Leaders' Shield with a 36-16 win at Wakefield.
Ben Barba may be set to leave St Helens, but Cronulla Sharks cannot afford to re-sign the 2016 NRL winner.
St Helens saw their unbeaten streak in Super League come to an end as they were upset by Huddersfield on home soil.
St Helens stalwart Jon Wilkin has revealed he is considering his options after deciding to leave St Helens at the end of the season.