The Kansas City Royals managed to end their recent struggles at home by carrying over some momentum from a winning road trip.
Kansas City (19-19) won four of the final six games on a West Coast trek before topping Colorado 5-1 in its return home Tuesday. Lorenzo Cain and Salvador Perez homered to help the Royals end a season-high four-game skid at Kauffman Stadium.
Vargas (3-1, 3.04 ERA) will attempt to follow that effort by building on one of his best outings of the season. The left-hander yielded three hits over seven innings and matched a season high with six strikeouts in a 6-1 win against one of his former teams, Seattle, on Friday.
Vargas had given up 12 runs and 21 hits over 11 1-3 innings in his two previous starts.
''When he's on his game, like he was tonight, he really works the accelerator really well," manager Ned Yost said. "He pushes down with the fastball, backs off with the changeup. Good curveball.
"What pitchers like Vargie do so well is they disrupt the opposition hitters' timing. He did that extremely well tonight."
Vargas will face a Colorado team batting .217 during a 1-4 stretch and has a combined 22 strikeouts in the past two games, including a season-high 12 Tuesday. The Rockies (23-18) scored 11 of their 16 runs in the last five games in a win in Cincinnati on Saturday.
They batted .319 and averaged 6.8 runs while winning 15 of their previous 20. Carlos Gonzalez is among the least successful at the plate during Colorado's five-game funk, going 2 for 18 with five strikeouts.
Vargas will be opposed by Jhoulys Chacin, who had a solid outing in his second start back from a strained right shoulder. The right-hander gave up two runs and four hits over six innings Friday in Cincinnati but did not get a decision in Colorado's 4-3 defeat.
He gave up four runs, eight hits and five walks over five innings in his season debut, a 5-1 loss to the New York Mets on May 4.
"I'm feeling better and better, and hopefully next time I'll feel better," Chacin told the Rockies' website.
Chacin (0-1, 4.91) will make his first start against Kansas City while Vargas will make his fifth versus Colorado. He is 1-2 with a 11.42 ERA lifetime against the Rockies but gave up three runs over seven innings in his most recent matchup, a 10-3 win for Seattle on May 19, 2012.
Brandon Barnes is 4 for 6 against Vargas, but he's 1 for 9 with three strikeouts in his last four games. Nori Aoki has the most experience against Chacin among Royals' hitters, going 4 for 9 with three solo home runs.