Cardinals Named As Trade Fit For Diamondbacks Arm With Elite Changeup

The St. Louis Cardinals could go in several different directions with their trade deadline strategy.

No one knows for sure yet if St. Louis will buy or sell.

If the Cards did decide to add, president of baseball operations John Mozeliak would be tasked with improving the rotation.

On Tuesday, ESPN’s Kiley McDaniel and Jeff Passan linked an interesting name to St. Louis: Arizona Diamondbacks right-hander Merrill Kelly.

“Chance of trade: 30%," McDaniel and Passan wrote. "Kelly doesn't have big raw stuff, posting the second-lowest average fastball velocity among pitchers with 90 innings pitched this season. His changeup is his best pitch by a wide margin, and he gets by with location and off-speed stuff. He was a stalwart in the Diamondbacks' run to the 2023 World Series, striking out 28 in 24 innings with a 2.25 ERA. Best fits: Toronto (Blue Jays), Boston (Red Sox), St. Louis (Cardinals), Houston (Astros), Chicago Cubs.”

The 36-year-old Kelly has pitched well in 2025, posting a 3.39 ERA and 1.05 WHIP across 93 innings in 2025, with 93 strikeouts and just 25 walks.

Moreover, Kelly’s expiring contract ($7 million this season) makes him an attractive rental.

Kelly has pitched deep into the postseason and could provide some high-pressure performances for the Cardinals down the stretch of the regular season if making the playoffs is a priority for them.

The Diamondbacks may pivot to selling soon, and it sounds like St. Louis would be wise to monitor the situation.