Murray, from Regina, has eight goals and two assists in 116 career NHL games with Phoenix, Florida, Montreal and the New York Rangers.
The 27-year-old compiled 11 goals and 10 assists in 64 games for the San Antonio Rampage last season and also played 10 games with the parent club in Phoenix. Murray, who is six foot two and 215 pounds, was the 79th pick of the New York Rangers in the 2001 draft.
Saskatoon native Armstrong spent the last five seasons playing in the San Jose Sharks minor-league system and has appeared in two NHL games. The 25-year-old had 25 goals, 17 assists and 101 penalty minutes in 71 games for Worcester last season.