These players would fall under the professional tryout category or PTO. The advantage of a PTO is that if the player does not work out, the team can just cut them and move on without any financial penalty. If the player does work out, they could sign them to a league-minimum deal for one season.
Brett, the brother of Nick Ritchie, spent last season with two teams. He was with the Calgary Flames and then was traded to the Coyotes for his brother. He was drafted in the second round, 44th overall pick, in the 2011 entry draft.
He's known for his toughness and willingness to drop the gloves to defend his team. During his career, which has spanned the Stars, Bruins, Flames, and Coyotes, he has played 391 games, scored 50 goals with 35 assists for 85 points, and has a -13 rating.