"He pounded the zone," manager Matt Williams said. "We didn't let the guys at the plate know what was coming, [because we wanted to protect] Doug. He didn't have a screen in front of him. He threw everything for strikes. He worked pretty fast. He got a lot of pitches in today. He said he likes to feel tired and work through the tiredness. It was a good session for him today."
Desmond said Fister's changeup and sinker were impressive.
"He was competing. He was a little fired up. I like that," Desmond said. "I swung at a sinker, I swung over the top of it and it disappeared. He threw me a changeup and it looked exactly the same as the sinker. I can't tell the difference."
Rendon hit a home run off Fister during the session, but was still impressed by what he saw from the right-hander.
"He is tall and lanky, but he is fluid. He is so smooth on the mound. His ball just moves all over the place," Rendon said. "I wouldn't say I did well. It's just the first day."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.