Craig Stammen. (Photo by Greg Fiume/Getty Images)
Craig Stammen. (Greg Fiume/Getty Images)

Craig Stammen underwent successful surgery Sunday to repair two torn flexor tendons in his right forearm, according to a person familiar with the situation. The tendons were nearly completely torn. The good news for Stammen is that no ligament damage was found.

Stammen, 31, is expected to miss the rest of the 2015 season. He was given a 10-month recovery timetable by doctors and is expected to be back by spring training.

Before his injury, Stammen was one of the most durable and consistent relievers in baseball. No reliever had thrown more innings than him since the start of the 2012 season. Now a hampered Nationals bullpen will have to replace his workload.

Stammen first felt discomfort last week but made two appearances after he felt some improvement. He landed on the disabled list for the time in his career on Wednesday. He is due $2.25 million in 2015 and is eligible for free agency after the 2016 season.