The Arizona Diamondbacks still have work to do to avoid their first losing season in three years.Both second-place clubs will end their seasons Sunday at Chase Field.The 70-year-old Johnson, who will be managing for the last time Sunday, recently told his players he wanted to finish at least 300 games above .500 for his career.To help reach that benchmark, he even planned on starting Gio Gonzalez -- who had already been shut down for the year -- in Sunday's finale. But Washington (86-75) received seven innings of four-hit ball from Dan Haren against his former team in Saturday's 2-0 win, improving Johnson's all-time managerial record to 1372-1070, guaranteeing a career mark over .500."It's wonderful," Johnson said. "The effort was outstanding. I can't even put words on it. Tomorrow I'm going to play the young guys. Some of the other guys, their seasons are finished. They battled hard. I really thanked them a lot for the effort and I know they're in a good place moving forward."Meanwhile, the Diamondbacks (80-81) are one win shy of finishing with the exact same record as last season. They haven't finished below .500 since a 65-97 mark in 2010.Saturday marked their fourth straight defeat and fifth in six games, a span during which they've totaled 11 runs while hitting .177. Paul Goldschmidt remains one of the few bright spots, singling Saturday to extend his hitting streak to 18 games. He is tied with Pittsburgh's Pedro Alvarez for the NL home run lead after Alvarez hit his 36th on Saturday."We just haven't hit," manager Kirk Gibson said. "We scored 11 runs in six games. He (Haren) pitched a good game and we give him credit, but you have to have better opportunities and make the most of your opportunities."Arizona will try to produce more offense as it sees Washington rookie Tanner Roark (7-1, 1.74 ERA) for the first time. He won his first three big league starts while posting a 0.95 ERA before allowing season highs of four runs and nine hits over five innings in a 4-3 loss Monday at St. Louis. The right-hander surrendered the first homer of his career to Carlos Beltran."I didn't have fastball command and I was getting behind hitters," Roark said. "If you do that against a good team, they're going to hit your mistakes."Diamondbacks left-hander Wade Miley (10-10, 3.63) was a 3-2 loser at Washington on June 26, allowing three runs -- two earned -- and seven hits over seven innings. He was 1-1 in his previous two matchups with the Nationals with a 3.48 ERA.With 195 2/3 innings, Miley will try to reach the 200-inning mark for the first time in his career.Ryan Zimmerman, 2 for 25 over his last six games, is 4 for 7 off Miley with three doubles and three RBIs.