Miller was knocked to the ice by Lucic when the goalie strayed from his net to play the puck in the first period of the Sabres' 6-2 loss to Boston on Saturday.
Lucic served a two-minute penalty for charging. Miller gave way to backup Jhonas Enroth started the third.
"I had the hearing because I did make an initial assessment of the play as I do with all plays, but I did have some questions for Milan and I wanted to hear directly from him," Shanahan told NHL.com. "They were regarding his intent; at what point did he know there was going to be a collision; and whether or not he felt he had the time to avoid the collision.
"I was satisfied with his answers."
Enroth got the start the Montreal Canadiens on Monday night.
"It just means that teams will be to able do exactly what Lucic did," an unimpressed Buffalo coach Lindy Ruff told reporters. "Your goaltender can play the puck, we can run him over, we can hurt him and all you get is a two-minute minor penalty.
"That is essentially what that means - You can concuss the other team's goalkeeper ... it means it's fair game on goaltenders again."