Curtis Sironen and Api Koroisau had plenty of reasons to smile upon returning to pre-season training on Monday.

For Sironen, it marked an end to 220 long days on the sidelines after suffering an ACL injury in the round four win over Canberra at Lottoland.

As for Koroisau, the Fijian hooker hasn't played since suffering a fractured right foot in the round 14 loss to the Warriors in Christchurch in June.

The pair's experience and skills were sorely missed as they frustratingly sat on the sidelines. Fortunately for Manly supporters, they still have plenty of time to showcase their abilities with both contracted to the Sea Eagles until the end of 2021.

Sironen said one of the hardest parts during his time out was dealing with the mental side of it.

"You get your surgery done and then you become sort of out of sight, out of mind,'' Sironen said.

"And that's no one's fault. But you do get separated from the playing squad as they are focusing on their training for the match ahead and you are doing your rehab work, so you might only see the boys once a week.

"I know my character and mental resolve is going to be so much better next year after seeing what the boys went through in what was a disappointing year.

"I've already got round one circled against my former club, Wests Tigers. It's at Leichhardt Oval and I naturally spent a lot of time there growing up through my family.

"I haven't played there since I left the Tigers, so that's an immediate goal of mine to play in that match. I will certainly be ripping into training to make that team."

Whilst Sironen is back running, Koroisau is on light duties after recently having screws taken out of his ankle. Both players are expected to be right for round one.

"It is just great to be back. You don't look forward to being flogged at pre-season training but one of the things you do enjoy about it is being with your team-mates again,'' Koroisau said.

"I have a few more weeks until the stitches come out and then I will slowly get back into it. I am keen for a big year and I can't wait to start training.

"The most frustrating part of being out for so long is just how helpless you are to the team. It was tough to watch, especially the back end of the season.

"We have a really good so I am really excited about the year ahead."

Meanwhile, talented young centre Moses Suli is experiencing his first full pre-season with the Sea Eagles.

Suli impressed many in his first season with Manly to earn himself a new two-year contract after only joining the club in March from the Bulldogs.