The move was made official on Friday after months of speculation surrounding the future of the 20-year-old.

After playing seven NRL games with the Dragons and establishing himself as a future representative player, Saab won his long-term battle with the club to secure a release.

A player swap was originally explored between the clubs but the Dragons finally settled on an undisclosed transfer fee paid by the Sea Eagles.

Saab will start training with Manly next week.

It's understood Saab was angling for a release to a Sydney-based club for personal reasons.

The commute from his home in Greystanes to Wollongong was one contributing factor.

However, joining the Sea Eagles will not save him much time as the trip north to Narrabeen from Sydney's west takes over an hour.

Regardless, it's a huge win for the Sea Eagles who are also expected to announce the signing of Wests Tigers forward Josh Aloiai as early as Friday.

It is set to kickstart a domino effect of NRL transfers, with the Tigers looking to sign big man Joe Ofahengaue from Brisbane.

A release of the former Queensland Origin star will then open the door for the Broncos to sign utility forward John Asiata from North Queensland.

Meanwhile, the Sea Eagles have also signed winger Christian Tuipulotu on a four-year deal from the Sydney Roosters after making his NRL debut earlier this season.

"Christian is a very talented young player. We are looking forward to further developing his game here at Manly,'' said coach Des Hasler.

"He is very athletic and will certainly bring added depth and competition for spots within the squad.

"Jason is a young, promising player. He has all the attributes to be a successful, consistent NRL player."

Australian Associated Press