Chairman Neil Hudgell says Adam Walker "owed" loyalty to Hull KR, after the prop said he will leave following their relegation from Super League.
Hudgell says Rovers supported Walker during child sex charges that were dismissed at Leeds Crown Court in May.
The Scotland international played 31 games for Rovers in 2016.
"I can't blame any player for wanting to play in Super League but in my opinion Adam is a special case," Hudgell said.
"We felt he owed us a year for the support the club has given him. Instead, he was the first to head for the hills."
"It was us who sat round the table with his legal team and repeatedly defended him in the face of criticism," added Hudgell.
"By contrast, his agent has crawled out from under his stone at the smell of cash to take his slice. It's a great disappointment for the club to lose Adam, but we will move on."
Meanwhile centre Thomas Minns has committed to Tim Sheens' side for 2017, following the decisions of Maurice Blair and Shaun Lunt.
Minns, 22, scored 20 tries in 23 Super League and Qualifiers games for Rovers, following his move from Featherstone.
"Thomas will be a tremendous asset for us in the Championship," head of rugby Jamie Peacock said.