Financial terms of the deal, announced Tuesday, weren't revealed.
The 23-year-old Galiardi played only 35 games last season because of wrist and forearm injuries. He finished with seven goals and eight assists. The Avalanche selected Galiardi in the second round of the 2007 draft.
Rissmiller, 32, played for five teams last season, including the Lake Erie of the American Hockey League. He was originally signed by the San Jose Sharks in June 2003 and has played in 192 NHL games.
That's today's game. That's one of the things you have to deal with when you're a championship team. Guys are going to earn more money based on their performance and what they've achieved, [and] deservedly so. [Saad] falls into that category.
— Blackhawks coach Joel Quenneville on Brandon Saad, who was traded by Chicago to the Columbus Blue Jackets this offseason