The Braves are 8½ games ahead of the St. Louis Cardinals in the NL wild-card race but face growing concerns about the health of their starting pitchers.
Right-hander Jair Jurrjens said Thursday an MRI on his sore right knee showed a bone bruise and he plans to see orthopedic specialist Dr. Richard Steadman in Vail, Colo., on Friday. Jurrjens could join right-hander Tommy Hanson (sore right shoulder) on the disabled list.
"It is a concern, sure," manager Fredi Gonzalez said. "You want to make sure (Jurrjens) is healthy."
Hudson (14-8) allowed one run and five hits in six innings while passing Jurrjens for the team lead in wins. The right-hander improved to 5-1 with a 2.03 ERA in his last seven starts.
"I think we're so deep in the staff, if we had to go into the postseason with D-Lowe and Huddy and Beachy, we're OK with that," Jones said.
Jonny Venters yielded a run in the eighth before striking out two batters with the bases loaded. Craig Kimbrel gave up a single to Wilson Ramos but struck out the side in the ninth for his 42nd save, extending the major league rookie record he set Wednesday night.
Hudson wasn't happy when he was lifted for pinch-hitter Matt Diaz with two outs and two runners on base in the bottom of the sixth.
"To be honest with you, I was going to try to hit a three-run homer," Hudson said.
Hudson acknowledged he never wants to come out of games "regardless of if I'm pitching well or giving it up." He leads the Braves with 183 innings pitched.
"My innings have gotten to a pretty high number, so it might be smart at this point of the year to start backing off and saving it for the stretch," Hudson said.
Nationals manager Davey Johnson said the right-hander was "the usual Tim Hudson."
"Didn't give in," Johnson said. "Kept his team in the game."
Chien-Ming Wang (2-3) gave up four runs and seven hits in 5 2/3 innings for Washington, which has lost eight of nine.
McCann hit his 23rd homer in the first inning. Jones, who hit his 450th career homer on Wednesday night, went deep in the second.
Jayson Werth led off the sixth with a long homer to left.
Atlanta led 4-1 before Washington rallied in the eighth. With one out and the bases loaded, Michael Morse hit a grounder to third baseman Jones, who dropped the ball for an error as he was preparing to throw to second to start a possible double play. Jonny Gomes, who reached on an infield single, scored from third.
"He's a heck of a pitcher," Johnson said of Venters. "He's had a heck of a year. I thought Flores had some pitches to hit. He's usually pretty good in that situation. We just didn't get it done. It's been kind of the same song all year long.
"We battled. We got to the point where we got a chance to do something. We just didn't do it," he said.
Washington right fielder Laynce Nix left the game in the third inning after straining his right groin.
Johnson said Nix "will be out for a while" because groin injuries take time to heal.
Braves first baseman Freddie Freeman did not start due to a sore right quadriceps muscle. Eric Hinske filled in for Freeman and had a run-scoring single in the fourth. Freeman replaced Hinske in the seventh.
The Braves recalled catcher J.C. Boscan and right-hander Anthony Varvaro from Triple-A Gwinnett. ... Braves infielder Jack Wilson, acquired from the Seattle Mariners on Wednesday night for a player to be named and cash, joined the team. Wilson is on the 15-day disabled list with a bruised left heel and is eligible to be activated on Friday. ... Left-hander Dustin Richardson was designated for assignment to make room for Wilson. ... Beachy will face Los Angeles Dodgers right-hander Chad Billingsley in the first game of a weekend series on Friday night. ... The Nationals will open a home series against the New York Mets on Friday night. Left-hander Ross Detwiler will face New York knuckleballer R.A. Dickey.