(AP Photo/Evan Vucci)

After the Nationals’ 10-3 loss to the San Francisco Giants on Friday night, starting pitcher Doug Fister revealed he had recently underwent a procedure to remove cancerous skin from the left side of his neck.

“I had some skin cancer removed a couple days ago,” Fister said. “It had no effect tonight.”

Fister did not say anything further about the operation, other than that he is fine now. A Nationals media relations official cut short a group interview a second after he explained why stitches ran down the side of his neck.

During a rare loss Friday night, Fister allowed four runs over six innings. Out of respect for Fister’s privacy, Manager Matt Williams declined to address the reason behind the stitches, but he said Fister was okay.

“Everything’s good with him,” Williams said. “He’s fine.”

Skin cancer is a scourge among baseball players, coaches and scouts who spend hours daily under the summer sun.

Fister insisted he never thought of the issue Friday night as he fought to find his mechanics and preserve the Washington Nationals’ winning streak, which ended at 10 games. He said it had no impact on his performance, however difficult that may be to believe.

The Nationals had gone 14-3 in his last 17 starts, and Fister had not allowed either multiple homers or more than three runs in a single start since June 15. He gave up four runs on two homers to Giants on Friday.

“I just wasn’t sharp,” Fister said. “I left too many balls over the plate.”