PHOENIX -AP- Rookie Brock Stewart pitched five effective innings and the Dodgers bullpen took over from there Saturday night as the NL West leaders beat the Arizona Diamondbacks 6-2.The Dodgers started the day with a four-game division lead over San Francisco.Joc Pederson hit a two-run homer, his seventh in 13 games against Arizona this season. He lined a 3-2 pitch from Shelby Miller (2-12) over the pool in right field at Chase Field in a three-run fourth. Stewart (2-2) beat the Diamondbacks on Sept. 7 at Dodger Stadium for his first big league win. He earned another victory, giving up two runs and five while striking out six and walking one.Five Los Angeles relievers shut out the Diamondbacks on one hit over four innings.Corey Seager tripled and scored on Justin Turner's sacrifice fly in the Dodgers first.Jean Segura homered in the bottom half to tie it. He has three leadoff homers in the past five games and 17 on the season.With two on and none out in the fourth, Diamondbacks catcher Welington Castillo retrieved a pitch that got away and tried to throw out Adrian Gonzalez at third, but the toss sailed into left field and let a run score.Pederson followed with his 23rd home run of the season.Chase Utley doubled twice for the Dodgers.Miller allowed four runs on seven hits in 5 1/3 innings and hasn't won in the majors since June 20.Castillo homered in the fourth. The Diamondbacks almost scored more, but Dodgers left fielder Andrew Toles threw out Yasmany Tomas at the plate.CATCHER CALLUPThe Diamondbacks brought up catcher Oscar Hernandez from Double-A Mobile before the game. He had gone home to Venezuela after his minor league season ended.