The St. Louis Cardinals hit the road to face the Arizona Diamondbacks at Chase Field on Friday, July 17, with first pitch scheduled for 9:40 PM ET. Arizona will send right-hander Merrill Kelly to the mound, while the Cardinals have not yet announced a probable starter. St. Louis will look to pick up a road win in a matchup that carries real weight in the second half of the 2026 season. Fans can catch the action on Cardinals.TV Presented by bet365 or listen on KMOX 1120 AM/104.1 FM.

Cardinals vs. Diamondbacks: Pitching Matchup and Lineup Overview

The big question heading into Friday night is who takes the ball for St. Louis. With no probable pitcher listed, manager Oliver Marmol will have some explaining to do before first pitch. It is worth watching whether the Cardinals turn to a bulk reliever, a fresh arm from the rotation, or someone making a spot start.

On the Arizona side, Merrill Kelly draws the assignment. Kelly is one of the more experienced arms in the Diamondbacks' rotation and has a track record of eating innings and keeping his team in games. Without current ERA or win-loss data available, the situation on the mound for Kelly bears watching as the Cardinals' lineup prepares to face him.

St. Louis Cardinals Starting Lineup at Arizona

• 1. JJ Wetherholt, 2B
• 2. Iván Herrera, DH
• 3. Alec Burleson, 1B
• 4. Jordan Walker, RF
• 5. Lars Nootbaar, LF
• 6. Masyn Winn, SS
• 7. Nathan Church, CF
• 8. José Fermín, 3B
• 9. Jimmy Crooks, C

Arizona Diamondbacks Starting Lineup

• 1. Ketel Marte, 2B
• 2. Geraldo Perdomo, SS
• 3. Corbin Carroll, RF
• 4. Gabriel Moreno, C
• 5. Max Kepler, LF
• 6. Lourdes Gurriel Jr., DH
• 7. Nolan Arenado, 3B
• 8. Ildemaro Vargas, 1B
• 9. Tim Tawa, CF

Keys to Watch for the Cardinals

JJ Wetherholt Sets the Tone at the Top

The Cardinals are running rookie infielder JJ Wetherholt at the top of the order. How Wetherholt handles a veteran starting pitcher like Kelly in his early at-bats will go a long way toward determining whether St. Louis can generate early offense on the road.

Jordan Walker and Alec Burleson in the Heart of the Order

The Cardinals need production out of the middle of their lineup. Jordan Walker bats cleanup and Alec Burleson hits third, giving St. Louis a pair of young, physical right-handed bats who can do damage in the desert heat at Chase Field. If Kelly can be worked deep in counts early, those two have the tools to take advantage.

Arizona's Nolan Arenado Factor

It will not be lost on Cardinals fans that Nolan Arenado — who spent a decade as the face of the St. Louis third base position — is now hitting seventh in Arizona's lineup. His bat and glove remain a threat, and he will be familiar with any Cardinals pitching staff tendencies. Expect the St. Louis dugout to be well aware of where Arenado fits in the Arizona order.

Pitching Depth and Bullpen Management

With no starter announced, the Cardinals' bullpen could be taxed on Friday night. Managing innings against a competent Arizona lineup — one that features Ketel Marte leading off and Corbin Carroll in the three-hole — will require sharp execution from whoever takes the ball for St. Louis.

Prediction

This is a tough draw. Hitting the road late at night against a known starter while your own rotation card remains blank is not an ideal setup. Arizona's lineup has legitimate threats up and down the order, and Chase Field can play differently in July heat. That said, the Cardinals have the offensive firepower in Walker, Burleson, and Nootbaar to put up runs if they can work Kelly into the middle innings. Call it a close game that likely comes down to which bullpen holds up. Edge to Arizona at home, but do not be surprised if St. Louis steals one on the road.