HOUSTON -- The Pirates, while five games below .500, are not that far behind in a National League Central division race where Pittsburgh, tied with Cincinnati in last place, is separated from first by just six games.

The Pirates' key to staying afloat in their division, and in an even more wide-open NL Wild Card race, will be their pitching. It has to get healthy, stay healthy and find consistency, while plowing through a schedule that does not let up until a month from now.

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In that respect, there's optimism to draw from the Bucs' 5-1 loss to the Astros on Tuesday at Minute Maid Park. Right-hander Trevor Williams, one of the rotation anchors who missed significant time this season with an injury, faced one of the most potent offenses in baseball, and while he wasn’t perfect, Williams pitched efficiently enough to last into the seventh inning.

"I'm thankful I'm healthy and that my body feels great," Williams said. "I'm thankful [manager] Clint [Hurdle] let me go out for the seventh. For me to go out for the seventh and get to 100 pitches, to do that is only going to help me next start."

In his second start since returning from a month-long stay on the IL due to a right side strain, Williams allowed four runs and eight hits over 6 2/3 innings in a 100-pitch outing against the Astros, whose injury-riddled lineup is slowly being put back together. Jose Altuve (1-for-4) returned a few days ago, and George Springer (also 1-for-4) played Tuesday for the first time since a hamstring strain sidelined him four weeks ago.

If the Astros, 20 games over .500, even without several key players for more than a month, could be viewed as a litmus test for the Pirates' top-of-the-rotation starters, it's fair to say that Williams received passing grades in this one. 

"It was good to see him go deep in the game," Hurdle said. "They've got to pitch to get better. It's a good lineup that he was able to face and work through. To go out for the seventh inning, I think those four [top-of-the-order] guys were 1-for-9 against him throughout the night. The pitch efficiency was a plus, a step in the right direction."

For the Pirates to survive these next few weeks leading up to the July 31 Trade Deadline, they are going to need stability from a rotation that has been in disarray from the beginning. The schedule is unforgiving. After their series in Houston, the Pirates play only the Brewers and Cubs until the All-Star break, and immediately after, they have series with the Cubs, Cardinals and Phillies, through July 25. 

Playing this stretch with a rotation that somewhat resembles what they envisioned before the season began -- including Williams and Jordan Lyles, who is due to return from the IL this weekend -- gives reason for optimism. 

Williams allowed seven runs over five innings in his prior outing against the Tigers, though he appeared to grow stronger toward the end of the 69-pitch performance. Tuesday's outing provided further confirmation that he's progressing. 

"I felt ready to pitch last start, but just sharpness, and stuff-wise, it wasn't there because I hadn't pitched in a big league game in 34 days," Williams said. "We're on the right track. I'm healthy. I'll reassess tomorrow and look over some ABs and pitches that I wish I could have back. But overall, we're on a steady climb upward and getting back on track."

Williams yielded a two-run homer to Yuli Gurriel in the fourth, but it was the 92 mph fastball down the middle of the plate to Alex Bregman in the sixth -- which Bregman sent to left field for his 22nd homer of the season, putting the Astros ahead, 3-1 -- that Williams regretted the most.

“It wasn't the dagger, but we needed a shutdown inning, especially scratching one run off Gerrit [Cole] and keeping it a 2-1 ballgame,” Williams said. “I didn't do my job right there to shut down.” 

Earlier, many observers assumed the story of this game would be Cole, who was facing his former teammates for the first time since the Pirates traded him to Houston on Jan. 13, 2018. But Cole, who entered this outing averaging 13.8 strikeouts per nine innings, wasn't quite as overpowering. In six innings, he fanned only three, though he held the Bucs to just one run, which came in the sixth inning when Melky Cabrera singled home Corey Dickerson, who led off with a double. The Pirates created significant traffic on the basepaths against Cole, especially in the sixth, when they had the bases loaded before Elias Diaz grounded to first to end the threat. 

"It was one of those games where you're looking for the big hit," Hurdle said. "And we didn't get it."