While the Arizona Diamondbacks have long since surrendered the NL West lead, they are still very much alive in the playoff race.Slumping Pittsburgh looks to get back on track Sunday in this series finale against visiting Arizona, which is coming off its biggest offensive outburst of the year.The Pirates (72-50) looked like contenders in 2011 and 2012 before falling off, and they've suddenly lost six of eight -- tied for their worst eight-game stretch of the season.Pittsburgh is still two games ahead of second-place St. Louis in the division and 8 1/2 clear of the Diamondbacks (63-58) for a playoff spot.Arizona sat atop its division for nearly two months before Los Angeles took over in late July. Though the Diamondbacks are also 8 1/2 behind the Dodgers, they are just five games back of Cincinnati -- which they'll visit for four games starting Monday -- for the second wild-card spot after winning seven of 10.Arizona bounced back from Friday's 6-2 loss at PNC Park with Saturday's 15-5 rout.Martin Prado went 4 for 5 with a three-run homer and Paul Goldschmidt collected three of the team's season high-tying 20 hits, including a three-run shot of his own. Wil Nieves had three RBIs while Didi Gregorius, pinch-hitter Jason Kubel and pitcher Trevor Cahill all drove in two."I feel like this is the beginning of what we should do from now on," said Prado, who scored a career-high four runs. "I feel like everybody contributed. We're hoping to keep having this offense all the way through the end of the season."Goldschmidt's 30 homers are tied for the NL lead with Pirates third baseman Pedro Alvarez, who also connected on a three-run homer Saturday. Goldschmidt has nine home runs during a 21-game stretch, while Alvarez has three in his last six.Alvarez will try to stay hot against Diamondbacks starter Wade Miley (9-8, 3.63 ERA), who is 5-1 with a 2.01 ERA in eight outings since the beginning of July. The left-hander had posted a 0.86 ERA during a season-high three-start winning streak before yielding four runs in seven innings of Monday's 7-6 walkoff win over Baltimore."I really didn't have good stuff, I was just pitching with my fastball," he told MLB's official website. "I just tried to battle and get through it."Miley yielded two runs in 6 2/3 innings to beat Pittsburgh 10-2 on April 10, improving to 2-1 with a 2.04 ERA in the series.Neil Walker, Garrett Jones, Jose Tabata and Russell Martin are a combined 0 for 13 versus Miley, but Starling Marte is 3 for 6 with a double.The Pirates will try to get back on track behind Charlie Morton (4-3, 3.79). The right-hander allowed two runs in six innings of Tuesday's 4-3, 14-inning loss at St. Louis."He gave us a good start," manager Clint Hurdle said of Morton, who held Miami to two runs over seven innings in his previous outing. "He has good command of the fastball."Morton limited the Diamondbacks to three hits over six innings in a 5-3 win in Phoenix on Sept. 20, 2011 -- his most recent start versus Arizona.