Gsellman is expected to be sidelined 6-to-8 weeks with a torn right lat, Steve Gelbs of SportsNet New York reports.
The 27-year-old was placed on the injured list earlier in the day and is now facing an extended absence dur to the injury. It's unclear if Gsellman will require surgery, but he'll be unavailable until at least early August if the initial timeline holds throughout his recovery.