The Calgary Stampeders have added four import players to their practice roster — quarterback Darron Thomas, receiver Marcus Rivers, linebacker Alvin Bowen and defensive back Jeremy Caldwell.

Thomas was a standout at the University of Oregon and holds the school record with 66 career touchdown passes including at least 30 in each of his two seasons as the starter (2010 and 2011). He was second-team all-Pac 10 in 2010 and was a finalist for the Davey O’Brien Award as the top quarterback in the country in 2011.

Rivers played four seasons at the University of Buffalo. He had 50 catches for 690 yards and five touchdowns as a junior in 2010 and followed that up with 60 catches for 615 yards and two scores during his senior season. Earlier this year, he signed with the NFL’s Green Bay Packers as an undrafted free agent.

Bowen was drafted by the Buffalo Bills in the fifth round (147th overall) of the 2008 NFL draft and appeared in two regular-season games for the Jacksonville Jaguars in 2010. He played three seasons at Iowa State and collected 287 tackles, including 19.5 tackles for loss, four sacks, three interceptions and six forced fumbles. As a junior in 2006, he made 155 tackles and led the country with an average of just under 13 tackles per game.

Caldwell was a four-year starter at Eastern Kentucky and also excelled on kick returns. He was twice named to the all-Ohio Valley Conference first team and scored seven touchdowns over his career including three on interception returns, three on kickoff returns and one on a punt return. As a sophomore in 2009, he led the Ohio Valley Conference with seven interceptions and had a total of 15 picks during his career.