HOUSTON -- When Lance McCullers Jr. injured his right forearm in Game 4 of last year’s American League Division Series, the Astros’ pitching staff was in dire shape. Justin Verlander was already out for the entire season, an ineffective Zack Greinke had been moved to the bullpen and Jake Odorizzi had been left off the ALDS roster.

The Astros patched their rotation together in the AL Championship Series enough to beat the Red Sox in six games, even though their starters posted a 6.64 ERA in that series. The hero was lefty Framber Valdez, who threw eight innings of one-run ball in Game 5 to push the Astros to the brink of a pennant they eventually won.

The lack of starting pitching depth finally caught up with the Astros in the World Series, when their starters posted a 7.20 ERA and threw only 20 innings in six games. This year, as the Astros steamroll towards their fifth AL West crown in the last six seasons, starting pitching has been their linchpin.

Verlander has bounced back incredibly well from his Tommy John surgery and is the front-runner for the AL Cy Young Award, and Valdez has joined him to form a dominating 1-2 in the rotation. Valdez threw his 19th consecutive quality start in Thursday’s 7-3 win over the Rangers at Minute Maid Park, allowing four hits and one walk while striking out eight batters in seven scoreless innings.

“He threw an outstanding game,” Astros manager Dusty Baker said. “He was very serious about his work and he was very composed. They had him in a little bit of trouble there early and he settled down. He was outstanding, especially in the middle innings.”

The Astros have the lowest ERA among starting pitchers in the AL (3.16), with Verlander (15-3, 1.85 ERA) and Valdez (11-4, 2.73 ERA) leading the way. The workhorse Valdez leads the AL with 142 innings pitched, and needs one more quality start next week in Chicago to tie Mike Scott’s franchise record of 20 in a row, set in his National League Cy Young season of 1986.

“I feel proud of it,” Valdez said. “This is something that’s [close to] a record for the team, a record for me, as well. It’s something that, I think, just shows the fruits of my labor, the fruits of all my dedication and all the hard work I've put in.”

Valdez had all four of his pitches -- sinker, curveball, cutter and changeup -- working effectively on Thursday. He had 21 swings and misses, including 10 on his curveball -- his best pitch. He sent down 15 of the final 17 batters he faced, getting a pair of strikeouts to end his day after the Rangers put runners at first and third with one out.

“He was what we thought he was,” Rangers manager Chris Woodward said. “His ball was moving and his curveball was good. He got a lot of weak contact. We were able to pressure him late, but just couldn't seem to get that big hit off of him."

Veteran catcher Martín Maldonado, who’s caught all but one of Valdez's 22 starts, cranked a three-run homer in the second inning, and third baseman Alex Bregman hit a two-run homer in the fifth to make it 5-0. That’s pretty much insurmountable with Valdez dealing.

“It’s been really impressive,” Bregman said of Valdez. “He competes every single time out there, pounds the zone with strikes, keeps us on our toes defensively. He has four pitches that are quality, and just the competitiveness in the zone, the ground balls, the ability to string together good outings and the ability to continue to compete throughout the course of the season is awesome.”

Valdez, who got the win in the All-Star Game this year, has thrown more innings than he has in any big league season, and still potentially has as many as 10 starts remaining. Then it’s on to the postseason, where he'll join Verlander as one of Houston’s rotation anchors and will continue to be asked to eat innings and get outs.

“My body feels good,” he said. “I’ve been working really hard just to be able to throw all these innings and just continue to be able to throw a lot more innings to help the team and be able to do a great job for the team on the field.”