George was tied for ninth in the league with six sacks last season. He also recorded 19 tackles and a fumble recovery while appearing in all 18 games for Saskatchewan.
Over six CFL seasons, George has posted 95 defensive tackles and 21 sacks.
Patrick, a safety, spent the last five seasons with Riders after signing as a free agent in 2008 out of Stillman College. In 2012, he had his worst statistical year since his rookie season, registering 40 tackles and no interceptions.
Patrick was an all-star in 2010, when he recorded 68 tackles, nine interceptions and a touchdown. He has 227 defensive tackles, 18 interceptions and two sacks in his career.
DeAngelis, from Niagara Falls, Ont., is a three-time all-star kicker. He was the outstanding Canadian of the 2008 Grey Cup, where his five field goals helped the Calgary Stampeders beat the Montreal Alouettes 22-14 at Olympic Stadium.
DeAngelis connected on 30 of 39 field goal attempts last season with the Riders. Over eight CFL seasons with Calgary, Hamilton, Montreal and Saskatchewan, he has connected on 280 of 341 field-goal attempts.
The Roughriders also announced that they have released receiver Clay Cooke, who spent most of last season on the practice roster as an eligible junior.