Cardinals second-year starter Shelby Miller took a step back after several steps forward Tuesday against the Cubs - and Mike Matheny took notice of the reasons why.

Miller had recently stopped overthrowing his four-seam fastball and began to rely more on curves and sinkers, according to Fox Sports. The result was six straight quality starts and a 1.62 ERA during that stretch. He yielded neither a home run nor a walk in three of those outings. But he tossed plenty of four-seamers against the Cubs despite his inability to keep it down. He gave up three runs in 4 1/3 innings and displeased Matheny in the process.

"He was OK," Matheny said. "It was working at the beginning, striking out three of the first four guys he saw with fastballs at the top of the zone. Seemed like he had that late life. That's also a dangerous way to pitch, as we saw."

Miller, who fanned a season-high eight despite his short time on the mound, is 10-9 with a 3.74 ERA on the year.