Albion revealed on Sunday that they had reluctantly let Stagg go midway through a two-year deal so that he could stay in the Championship.
Director of rugby Graham Dawe although disappointed to lose an experienced campaigner, felt the ‘player’s wishes had to be paramount’, despite the fact that there was no automatic release clause in his contract in the event of relegation.
The 25-year-old has now joined fellow former Plymouth players Declan Cusack, Bevon Armitage, Tyson Lewis and Tyler Hotson at Castle Park.
He is no stranger to South Yorkshire having previously played for Rotherham.
Stagg said: “I’m very excited about the coming season here at Doncaster.
“Having spoken to (Director of rugby) Clive (Griffiths) at length, it is clear that he has great ambitions for the club. The squad is looking strong and I’m really looking forward to being a part of that.”
Griffiths said: “Ted has been on the circuit for a few years and knows the Championship inside out. He’s played at Rotherham and London Scottish as well as Plymouth last season and brings a wealth of experience and expertise beyond his years.”
Albion’s director of rugby Dawe had said on Sunday: “He will be a big loss, but he had an overwhelming desire to stay in the Championship so we came to a mutual agreement.
“A contract is a written agreement but a player’s wishes have to be paramount.”