According to manager Matt Williams, Fister is not expected to miss any starts and will pitch Wednesday against the Phillies.
"[Fister] knew about the skin cancer for some time," Williams said. "He took care of it. It's a fairly common occurrence. Because it's on his neck and he is on television, people noticed [the scar on his neck]. From all indications, everything was taken care of. He certainly will have further tests to make sure everything is good."
Third baseman Ryan Zimmerman said he didn't know about Fister's circumstances until he was approached by a member of the media Saturday afternoon.
"Doug is tough, obviously. He loves pitching," Zimmerman said. "He threw well last night. Doug threw some pitches that he would like to have back, but he has been so consistent. He has been a leader in this clubhouse. He is a big part of our pitching staff. His energy is infectious is the best way to put it."
Left-hander Gio Gonzalez said he is more concerned about Fister's health than with what he is doing on the mound.
"At the end of the day, last night's game did not matter as long as he felt fine," Gonzalez said. "That's all we care about. He has been a big part of so many great things we have accomplished this year. Last night, we just brushed [the game] under the rug. We just want a healthy Doug."
Fister is arguably the Nationals' best pitcher this season, going 12-4 with a 2.38 ERA in 19 starts. Right-hander Tanner Roark said Fister's work ethic is unbelievable.
"He is always in the weight room and running. Every time I always see him, he is back there working out," Roark said. "He is a huge asset to this team. The way he works, it's great for this offense as far as getting the team back in the dugout."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also can be found on Twitter @WashingNats. Daniel Popper is an associate reporter for MLB.com. He also can be found on Twitter @danielrpopper. This story was not subject to the approval of Major League Baseball or its clubs.