This game also has extra meaning for Oakland's Tommy Milone, who faces his former team for the first time in Friday night's series opener.
Fister spent the previous 2 1/2 seasons with Detroit before getting shipped to Washington in a four-player deal this winter. The right-hander, with a career 3.53 ERA, has yet to take the mound due to a strained lat suffered during spring training.
"I'm looking forward to just getting back to pitching - just in general," he told MLB's official website. "I'm pitching in Oakland. I've seen those guys a lot. It's going to come down to a big chess game. For me, I have to go out there and execute."
Fister has gone 1-4 with a 4.50 ERA while receiving a combined six runs of support in his last six regular-season outings against the A's, three of which came with Seattle in 2010 and '11. He also compiled a 3.46 ERA and went without a decision in two postseason starts against Oakland in 2012 and '13.
"They are very scrappy," Fister said of the A's, who tagged him for seven runs and 13 hits over five innings of a 14-4 loss Aug. 28. "They are a good ballclub. They hit the ball hard and bring every facet of the game (to the table)."
Milone (0-3, 5.86 ERA) will try to get the best of a Nationals team that sent him to Oakland in the Gio Gonzalez trade in 2011. The left-hander is 4-1 over a six-start stretch in interleague play despite a 4.46 ERA.
Milone hasn't had much go his way in the early going, though, as he's looking to avoid losing a third consecutive start after yielding 10 runs over 10 2-3 innings in his last two.
Milone, who received no runs of support in those outings, surrendered six runs and three homers over four-plus innings in Saturday's 6-3 loss at Boston.
"I got to make better pitches, throw more strikes. I just left them over the plate," said Milone, who had been taken deep once in his first four outings. "I'm leaving balls up and over the middle of the plate. I need to do a better job of throwing more quality strikes and keeping the ball low, and letting them hit it on the ground."
The A's (20-15) had dropped three straight and five of six before beating Seattle 2-0 in the second game of a doubleheader Wednesday. Yoenis Cespedes hit his sixth homer and Jed Lowrie went 2 for 4 with an RBI.
"We're just trying to digest this win after losing three in a row," manager Bob Melvin said. "This team's been pretty resilient over the years."
Washington (19-15) hits the road with momentum on its side after taking two of three from the Los Angeles Dodgers. Wilson Ramos, playing in his first game since breaking a bone in his wrist on opening day, doubled on the first pitch he saw and later drove in a run in Wednesday's 3-2 victory.
"I was waiting for this moment for about five weeks," Ramos said. "I'm happy to be here. It's good to be back on the team."
Washington has gone 8-6 on the road while slugging a major league-best .465, nearly 100 points higher than its home mark of .366.
The Nationals haven't faced Oakland since taking all three meetings at home in 2005. The franchises' only other series came in 2003, when Washington suffered a three-game road sweep as the Montreal Expos.