Yankees manager Aaron Boone said Thursday that Effross has been diagnosed with a Grade 2 left hamstring strain, Greg Joyce of the New York Post reports.
Effross suffered the moderate hamstring strain while delivering his one and only pitch during a Grapefruit League appearance earlier this week. The reliever has been given a platelet-rich plasma injection and is looking at an extended absence. Effross has made just 32 appearances over the last two seasons due to injury.