The 28-year-old forward, who was an unrestricted free agent, scored 24 points (15 goals, nine assists) in 44 regular-season games for the Colorado Avalanche last season and eight points (seven goals, one assist) in 10 Stanley Cup Playoff games.
"I'm excited," Saad said. "I'm looking forward to getting to know the city a little bit better, because when you play there, kind of in and out, you don't get to see all parts of the city. But I've heard great things, and they're obviously a great hockey team that I'm looking forward to joining and having another chance of winning and have that success. I think all the ingredients are there, and it's a team that definitely excites me, that's for sure, so I'm definitely glad to be a part of it."
Saad said the Blues' physical style suits his game.
"I think from playing against them, they play a heavy game," he said. "They like to hold on to pucks, cycle pucks, protect it, and that's all part of my identity as well. I think I can fit right into that aspect, as well as play a 200-foot game."