How Concerning Eduardo Rodriguez's Blowup Start vs Cardinals Really Is

In his first start of the second half, and since making his first career appearance in the All-Star Game, Arizona Diamondbacks left-hander Eduardo Rodriguez suffered his worst start of the season against the St. Louis Cardinals, in an extremely inopportune moment.

Rodriguez could not complete the third inning. Though he only issued two walks, he was knocked around for seven base hits, which set a lopsided five earned runs on his final line. He was pulled with two outs in the third for right-hander Drey Jameson.

Coming into this start with a sparkling 2.29 ERA, five runs is the most the left-hander has surrendered in an appearance this season. That number has now inflated to 2.62.

Diamondbacks' Eduardo Rodriguez suffers worst start of 2026

Jul 5, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Eduardo Rodriguez against the Milwaukee Brewers at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | IMAGN IMAGES via Reuters Connect

Of Rodriguez's seven hits allowed, four of them came on pitches either in the lower third of the zone or below the zone. The Cardinals showed a similar approach to what they pulled off in the sixth inning of Saturday's game against Brandon Pfaadt, knocking ground balls on low pitches.

Four of those hits were struck 100 MPH or sharper. The left-hander did not allow a home run, but did give up a sharply-hit double and a triple.

The triple scored a run from first base, partially due to a bit of a misplay in the outfield by rookie Ryan Waldschmidt. That pitch — a changeup — was a full baseball's width below the zone. That has been a strong out pitch for Rodriguez all season, and was even well-executed in that moment.

This is not to say that Rodriguez pitched well as a whole on Sunday. He did not look as sharp as he has for much of this season, and did not appear to have sharp command of his arsenal. He threw just 39 of his 68 pitches for strikes.

But is this start truly concerning, or simply a combination of bad location, rough defense and an unfavorable matchup?

Is Eduardo Rodriguez's blowup start major concern?

Jul 5, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Eduardo Rodriguez in the second inning against the Milwaukee Brewers at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | IMAGN IMAGES via Reuters Connect

In truth, Rodriguez's elite ERA number has been backed by less-than-outstanding peripherals all season. He came into the game with a 5.07 expected ERA. But his ability to execute in nearly every big moment has allowed him to post run-prevention stats that stand among the league's best.

With each passing start, one might have wondered when the regression was set to hit for Rodriguez, but it's also dishonest to call his ERA entirely fake. He has consistently executed in big moments and pitched with high levels of efficiency, even when he has not showed excellent command.

That simply did not happen Sunday. It would be a bit hasty to call this start the sign of a brutal second half to come. Rodriguez is likely due for a bit more regression, but this start — for now, at least — is much more of the anomaly than the trend.

The truly important part will be how Rodriguez responds to this start. If he comes out throwing a strong outing in his next appearance, this one can be chalked up to the variety of factors that turned it sideways. If not, it could be a sign of more intense regression still waiting.

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