Hansen elbowed the back of Hossa's head as they were both grappling for the puck early in the third period. He received a two-minute roughing penalty.
Hossa was motionless on the ice for a good minute before being helped up and walked to the locker room. Captain Jonathan Toews said the intention was very clear on Hansen's elbow to Hossa's head (via Scott Powers of ESPN Chicago):
I saw it when the puck was up. I saw the replay on the board. It was pretty evident he wasn't reaching for the puck or anything. I'm not too sure what's going to happen there. I'll have to see it a few more times to comment further, but I don't think there's any doubt there's contact to the head there. We just hope Hos is going to be OK.
Hansen, though, saw the hit as purely coincidental and maintained that he can't exactly say what really happened (via Chris Kuc of the Chicago Tribune):
We were both kind of jumping for (the puck). He grabs the puck first and as I'm coming down I kind of land on him a little bit. Apparently, I hit him in the back of the head is what the ref was telling me once I come down. It's hard for me to tell what really happened.
How long Hossa will be out has yet to be determined, but it is likely that he may sit a game or two at the very least as a precaution.
Having just been cleared in November from concussion-like symptoms, Hossa will be evaluated either Wednesday or Thursday to determine if those symptoms have returned.
If Hossa has to miss any significant time, the Blackhawks may put Daniel Carcillo on the top line with Jonathan Toews and Brandon Saad. More importantly, the Blackhawks will have to step up their offensive production with Hossa out of the lineup.
Follow James Maahs on Twitter for all the latest on the NHL and Chicago Blackhawks.