Kostin (upper body) was activated off injured reserve Friday, according to Curtis Pashelka of The San Jose Mercury News.
Kostin missed the Sharks' past five games due to the injury. Although he's now on the active roster, the 25-year-old is expected to be scratched Friday versus Vegas. That's not surprising because Kostin didn't have a secure spot in the lineup to begin with. He might get a chance to play Saturday versus Calgary.