"As the video shows" (below the fold), Brendan Shanahan took three key points into consideration: Alfredsson was injured on the play and did not return to the game, this was an elbow to the head, and Hagelin had no history with the department of supplementary discipline.
Hagelin was assessed a five-minute major on the play, which the Senators scored on.
Three games is about what I expected, although I'm always reticent to form expectations when the NHL disciplinary committee is involved. I don't think Hagelin is a dirty player, but this was most certainly a dirty play, and he deserves at least three games for it--especially considering the uncertainty surrounding Alfredsson's injury and, connected to that uncertainty, his NHL career. Still, I wonder what Hagelin might have been given had he been suspended before...
It feels as though justice has been served, but unfortunately that won't undo what's been done to Alfredsson. Sens fans around the world are now waiting with bated breath to find out the extent of Alfredsson's injury, and whether he returns this series.