The 23-year-old will try to continue his resurgence while helping the Cardinals avoid their third loss in four games on a road trip that continues Monday night against the Miami Marlins.
After going 0-3 with a 7.30 ERA over a five-start stretch, Miller (8-8, 3.99 ERA) was sent to the bullpen to work on his approach before replacing Carlos Martinez in his return to the rotation July 26.
Though he hasn't faced the fiercest lineups against the Chicago Cubs, San Diego and Boston, Miller has pitched more like the emerging ace the Cardinals (62-54) were expecting after he went 15-9 with 3.06 ERA in 2013 as a rookie.
The right-hander has allowed just five runs over 18 2-3 innings in his last three starts. He did not fare in the decision Wednesday when he allowed one run and four hits over seven innings in a 2-1 home loss to Boston.
His command has been much improved with one walk over his last three starts after issuing 20 in his prior six.
"He does look good now, without question," manager Mike Matheny told MLB's official website. "Before, I think, we were seeing some mechanics fall apart. He's in a good spot now, and hopefully can continue to build off of it."
Matheny's club seeks to even its record on this six-game trip after avoiding the sweep with Sunday's 8-3 win at Baltimore.
Rookie Kolten Wong tied a career high with four hits, while Jhonny Peralta added three and went 5 for 8 with two doubles and two RBIs in the final two games of the series.
''All the conversation was, we've got to win this, we've got to figure out a way to get this one,'' Matheny said Sunday.
Miller allowed three runs and a season high-tying nine hits over 5 1-3 innings in a 6-5 home loss in his only career start versus Miami on July 5. He did not factor in that decision as the Marlins eventually won their first series versus St. Louis since 2009.
Miami's Casey McGehee, who hit his third home run in Sunday's 7-2 loss at Cincinnati, went 7 for 13 with three RBIs in that set. Garrett Jones is 7 for 13 with two home runs and five RBIs versus Miller dating to his time with Pittsburgh.
Giancarlo Stanton hopes to continue his power surge after hitting his NL-leading 29th home run Sunday. The All-Star has six homers in his last 11 games and is 9 for 20 with two long balls in his last five at home versus St. Louis.
The Marlins (57-60), however, have averaged 2.7 runs and batted .198 while dropping seven of 11.
Right-hander Tom Koehler (7-9, 3.80) has posted a 2.92 ERA over his last four starts, but he's dropped his last two after allowing four first-inning runs and walking four over six innings in Wednesday's 7-3 loss at Pittsburgh.
Koehler, who hasn't given up an earned run in his last two home starts, gave up a career-high nine runs over 4 2-3 innings in a 13-7 home loss in his only start versus St. Louis on June 15, 2013.
The Cardinals' Matt Adams is 9 for 13 in his last five meetings versus Miami, though Matt Carpenter is 5 for 35 in his last 10.
St. Louis had won seven straight in Miami before dropping three of the last four.