Grandal, who went 3 for 5 with and scored three times, hit his 15th home run of the season off reliever Dominic Leone in the sixth inning.
Seager, who also had three hits, added his 18th off Steve Hathaway in the seventh, and Pederson got his 16th off Evan Marshall in the eighth to finish off the Dodgers' comeback from a 3-0 deficit in the fourth.
Jake Lamb scored Arizona's second run in the fourth inning on what was ruled a wild pitch. Stripling's pitch, called a ball, deflected off catcher Yasmani Grandal's throat guard and lodged inside his chest protector.
Home plate umpire Todd Tichenor ruled the play a wild pitch and advanced the runners one base, bringing Lamb home from third.
Patrick Corbin (4-10) gave up six runs and eight hits over 5 1/3 innings for Arizona, which lost for the 14th time in 19 games.
Seager was 7 for 13 in the series to raise his batting average to .310.
Puig, making his first start since July 20, reached base four times and scored twice. He has driven in 10 runs in his last 15 starts. Tightness in his right hamstring limited Puig to three pinch-hitting appearances over the previous eight games.
After Norris threw his second pitch to the game's second hitter, catcher Grandal hurried out to the mound waving trainers out of the dugout. After a brief exam and discussion that appeared to center around Norris' ribcage, the right-hander threw a pair of warm-up pitches before resuming. Norris retired Bourne on a popup before leaving the game.
Diamondbacks: RHP Zack Greinke will make his next rehab start with Double-A Reno on Wednesday night in Salt Lake City. Greinke will be on a five-inning/80-pitch limit. ... After Saturday night's game, Arizona traded RHP Tyler Clippard to the New York Yankees for prospect RHP Vince Compos, who was assigned to Triple-A Reno. RHP Evan Marshall was recalled from Reno to take Clippard's spot on the Arizona roster, his third stint with the team this year.
Dodgers: LHP Brett Anderson will make his next rehab start Tuesday for either Oklahoma City or Rancho Cucamonga, depending upon weather and travel considerations. ... OF Trace Thompson (lower back tightness) continues to progress toward a rehab assignment, taking batting practice, throwing and running, "sometime next week the goal," said manager Dave Roberts. ... OF Pederson, 2B Chase Utley and 1B Adrian Gonzalez were not in the Dodgers' starting lineup. Gonzalez pinch hit in the fourth, Utley came on in a double-switch in the sixth, and Pederson homered as a pinch hitter in the eighth.
Diamondbacks: RHP Archie Bradley (4-6,5.63) makes his first career start against the Nationals on Monday night at home. Despite losing three of his last four decisions, Bradley has allowed two runs or less in three of those outings.
Dodgers: RHP Brandon McCarthy (2-1,2.39) makes his sixth start since returning from more than a year recovering from Tommy John surgery at Colorado on Tuesday night. McCarthy began his comeback with five scoreless innings in a win over the Rockies on July 3.