Things to know about this game
• Koehler struggled against Washington last season, with a 5.33 ERA in four starts.
• The 12 home runs Koehler has given up to Washington are twice as many as he has allowed to any other team. The righty's toughest Washington nemesis has been Bryce Harper, who has homered five times in 26 plate appearances against Koehler, including three times last May 6. Jayson Werth and Ryan Zimmerman have gone deep off Koehler two times apiece.
• Saturday will mark Ross' first start against the Marlins. He faced Miami twice in relief last year, ceding two hits and no runs in 1 2/3 innings.
• With his first-inning single Thursday, Marlins left fielder Christian Yelich has hit safely in six straight games at Nationals Park.