Houston @ Arizona Game Overview

Pfaadt (10-6, 4.82 ERA) enters the game in Phoenix after arguably his best two starts of the season, one on either side of the All-Star break.

He pitched a career-high eight innings and allowed two runs on four hits in an 8-2 victory at San Diego on July 9.

A seemingly surprise choice to start the post-break opener Friday against St. Louis, Pfaadt blanked the Cardinals on four hits through seven innings in a 7-3 win.

His success has come with a renewed usage of his sweeper. Pfaadt threw a season-high 33 sweepers against the Cardinals, a predominantly right-handed hitting team.

"That's probably my best pitch and that's probably the best it's felt all year," Pfaadt said. "We went to it a lot, and it worked. Just trying to be efficient. Tried to make good pitches early on."

The Astros' lineup similarly features several right-handed batters.

The Diamondbacks bet on Pfaadt in the offseason when the sides agreed to a five-year, $45 million contract extension that kicks in next season. He had 11 wins in 2024.

Merrill Kelly and Zac Gallen are pitching on expiring contracts, and both have been mentioned as possible trade deadline pieces. Corbin Burnes is expected to miss most if not all of 2026 after undergoing Tommy John surgery in June.

Houston right-hander Brandon Walter (1-3, 3.66) will get the start in the series finale.

The Astros stretched their lead in the American League West to five games Tuesday.

Framber Valdez won his 10th straight game and rookie Brice Matthews hit a two-run homer in the eighth inning in a 3-1 win. Matthews has three homers in the last two games.

"These guys are fighting," Houston manager Joe Espada said. "This is a group that is not going to quit. Framber being Framber. We needed that."

The D-backs have lost two in a row after winning four in a row. They remain 5 1/2 games behind San Diego for the final National League wild-card berth with three other teams to pass.

Arizona loaded the bases on three singles to open the ninth inning but did not score. The Astros appeared to be willing to concede a run when Geraldo Perdomo singled with runners on first and second, but Josh Naylor was held at third before a strikeout and a double play ended the game.

"It was a gut punch today for sure," Diamondbacks manager Torey Lovullo said. "Held tight for seven innings, but we just couldn't close the deal."

Walter, who has yet to face Arizona in his career, has made eight starts while stepping into an injury-filled rotation. The Astros placed Lance McCullers Jr. on the injured list with a blister on his right finger before Tuesday's game, their seventh starter on the injured list.

Walter has made quality starts in each of his last two outings and five of his last seven. He gave up only three runs and five hits in his last two outings, but a lack of support saddled him with two losses.

--Field Level Media