Ross has allowed three earned runs or fewer in his each of his first seven starts. On Thursday, Ross pitched six solid innings in an 8-3 victory over the D-Backs.
"He understands if he makes pitches, he has a chance to get them out," Williams said about Ross. "We've seen so far that he doesn't walk a whole lot of guys and makes you put the ball in play and that's important. His ball has good late movement … and a good slider to go along with it for strikes when he needs it and out of the zone to get a swing and miss, too."
Fister, who led the led the Nationals with 16 victories last year, has had it rough in 2015, going 4-7 with 4.60 ERA in 15 starts. He last pitched on Monday against the D-Backs, throwing six innings and allowing five runs and three home runs. A finesse pitcher, Fister had problems keeping the ball down.
"[Fister] wants to pitch," Williams said. "He's willing to do whatever he can to help us win. So he was out [in the bullpen] today and he'll continue to be out there and get innings where we can get him innings. He's a team guy. He's ready to pitch at any moment to do whatever he can.
"It's a difficult task when you've been a starter for so long. The opportunities for him will be long. That's kind of where we see it. It's never easy but he's willing to go out there and do what he can to help us win a ballgame."
• First baseman Ryan Zimmerman received the day off for most of Thursday. Williams admitted that Zimmerman's left foot is sore. Zimmerman recently spent a month on the disabled list because of plantar fasciitis.
"The foot is going to be a little sore from time to time. It's just a day off," Williams said "It gives Clint [Robinson] an opportunity to get some at-bats as well to keep him sharp."
However, Zimmerman entered the game as a pinch-hitter in the seventh inning and doubled to center field, scoring Michael Taylor.
• Outfielder Reed Johnson is showing signs that he could be coming back to the Nationals before the season is over. Johnson ran the bases hard on Tuesday. The plan is to take a day off Thursday and run the bases again Friday. Reed has not played a game since late April after tearing a tendon in his left leg.
When the Nationals go on the long West Coast trip next week, Reed hopes to go on a rehab assignment.
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 and on his podcast. This story was not subject to the approval of Major League Baseball or its clubs.