Parcell joined Rovers on loan from Rhinos towards the end of the 2019 season and he scored crucial tries in wins over Hull and Leeds, though a shoulder injury restricted him to only five appearances.
He had a year remaining on his Leeds contract, but will not be returning to Emerald Headingley.
“It was always the plan to stay here for 2020 so it is great to get the deal sorted and have the opportunity to work with [head coach] Tony Smith again, which I really enjoyed,” Parcell said.
“I loved the freedom that I was given to play rugby here. Tony has given me that licence to play what’s in front of me and that is when I play at my best.
“The direction that the club is heading in, with all of the new signings, is exciting and I’m happy to be a part of that.
“Since I joined towards the back end of last season, the fans were nothing but exceptional towards me and I can’t wait to be back playing for them once more.”
Smith is "delighted" to be keeping Parcell in hs squad.
"Everybody that has seen him play will know what a great asset he is to us," he said.
"He is one of the most outstanding hookers in the game and one of the most dangerous runners too. With his experience, he adds great value to our squad.
"The hooker position is vital for us. The know-how and composure at dummy-half is crucial to the success of any team and we are grateful that Matt brings that to us."
Smith added: "Matt came in late towards the back end of the 2019 season, but he did remarkably well when being thrown in at the deep end.
"However, a full pre-season here will be of great benefit to Matt - he'll get to know our players even more and have a better understanding of how they play, and vice-versa.
"He has already shown what he is capable of, but pre-season gives him the opportunity to exceed what he has already shown."