The Edmonton Oilers announced via Twitter that Tyler Pitlick has suffered a lacerated spleen:
#Oilers forward Tyler Pitlick suffered a lacerated spleen during last night's game and remains in Calgary for further evaluation.— Edmonton Oilers (@EdmontonOilers) January 1, 2015
Pitlick played a surprisingly physical game against Calgary, reminiscent of the halcyon days of Mike Grier. Pitlick was likely injured during the hit pictured or when he decked Josh Jorris with an elbow. The injury wasn't an emergency, in fact, it may have felt like heartburn.
Typical causes of a ruptured spleen involve significant deceleration and impact with a large object, i.e. major crashes. Evens like car accidents, falls, professionally riding bulls and running into Teemu Hartikainen lead to collisions large enough to rupture spleens.
When I was a kid, a lacerated or ruptured spleen meant immediate surgery to perform a splenectomy which was followed by six weeks of convalescence before returning to life. Today, however, unless the spleen is damaged beyond repair, patients are typically monitored for internal blood loss and doctors allow the spleen to heal on it's own. Even if the blood loss is significant, a splenectomy might not be required as doctors can repair the spleen, though don't click that link if you're eating lunch...
If Pitlick is able to heal on his own, he could recover and be back in the lineup in as little as two weeks. If he isn't able to heal and requires surgery, he could be out for up to six.
For Pitlick, it's just another injury in a run of bad luck stretching back to being drafted by the Oilers. Since then, he's broken an ankle, injured a knee, suffered two concussions and a mysterious "upper body injury". His injuries have kept him out of the lineup for an entire season of games thus far in his career and he's just 23 years old.
As Ryan put it:
If Pitlick didn't have bad luck he wouldn't have any luck at all. Just one injury after another with him.— Ryan Batty (@ryan_batty) January 1, 2015