According to Sky Sports, Salford also have an option on the hooker for the 2016 season.
Salford owner Dr Marwan Koukash had earlier taken to Twitter to reveal that he had signed “Tomkins”.
The tweet came on the day that Koukash was celebrating the approval of a ‘marquee player’ rule, which would allow Super League clubs to exempt one star player from their salary cap.
“Started with a glass of wine this afternoon, ended up with few and resulted in us signing Tomkins. I am not kidding it is true,” Koukash tweeted.
Koukash also tweeted his delight at the approval of the marquee playe rule by the Super League clubs.
“Fantastic day for SL. The marquee player rule got voted through,” he tweeted.
“I know some people will be sceptic and I understand why, but today’s vote enable SL to compete with the NRL and Union for top talent.”
Koukash has often taken to Twitter in the past to make official announcements about his and his club’s decisions and recruitment.