The right-hander looks to win his fourth straight start when the Diamondbacks continue a four-game series with the visiting New York Mets.
Vargas, claimed off waivers from Washington on June 3, is 7-3 with a 3.69 ERA in 14 appearances, including 12 starts, for Arizona. He has allowed five runs over 20 innings in winning his last three outings, including Thursday’s 9-2 triumph at St. Louis.
Vargas surrendered two runs and five hits over six innings, striking out five and walking two.
“He’s been a gem,” Arizona outfielder Luis Gonzalez said of Vargas, who was 0-3 with a 9.24 ERA in four starts for the Nationals. “I’ll tell you what, we wouldn’t be where we’re at, at least in our black and blue division, without the way he’s been pitching.”
Vargas has yielded three earned runs or fewer in each of his last 10 starts for the Diamondbacks.
Arizona slipped back games behind first-place San Diego in the West with Monday’s series-opening 4-1 loss to the Mets.
Shawn Green drove in the lone run for the Diamondbacks, who have lost seven of their last nine games. Arizona opened a seven-game homestand, which will conclude with three against wild card contender Philadelphia.