Cristopher Sánchez has kept his walks down since returning. Here’s why the Phillies are optimistic it’ll stay that way.

On Friday night, Phillies manager Rob Thomson was asked if he had more confidence in Cristopher Sánchez in the fifth starter spot after his performance against the Nationals.

Thomson didn’t hesitate.

“Yeah, I do,” he said. “He’s been really good. We gave him the ball the first night in Oakland, and he’s kind of run with it. He’s given us good outings, and that’s what you need from your fifth starter.”

This isn’t to say that Sánchez will remain the fifth starter throughout the end of the season, or that the Phillies will choose not to add a starter at the trade deadline. But the left-hander is making a compelling case for himself. Earlier in the season, it didn’t seem like he would get the chance to do that.

After the Phillies sent him down to triple-A Lehigh Valley in April, Sánchez walked 23 batters through his first six starts while pitching to a 6.21 ERA. In his first start back with Lehigh Valley, he walked seven batters in four innings. But that number began to dwindle, and in his last two triple A starts, he walked only three.

The Phillies, who were eager to stop having a bullpen game every five days, had seen enough. Sánchez was recalled on June 17 and has a 2.40 ERA since. More importantly, he has kept walks to a minimum. He allowed only two through 15 innings in June, with 15 strikeouts.

» READ MORE: Phillies questions at midseason: Bryce Harper’s power outage, trade deadline outlook, and more

It is a small sample size, but in those three starts, Sánchez has provided something the Phillies needed: stability. By eating four, five, or, in the case of Friday night, six innings, he has allowed Thomson to preserve his bullpen. Catcher J.T. Realmuto put it well after a bullpen game in Arizona a few weeks ago. For those games to work, everyone has to be on, or at a minimum, pretty good. And more nights than not, that isn’t the case.

Having Sánchez pitch five or six innings allows for a better game plan. And now that he’s throwing strikes, Sánchez has been as effective as ever. He’s always had good stuff. It hasn’t overpowered guys — Sánchez is averaging about 92 mph on his sinker this year — but his pitches have a lot of movement, which is especially difficult to hit coming from a pitcher who is 6-foot-1.

“It’s a fast arm,” said pitching coach Caleb Cotham. “The sinker has tremendous sink and run. The changeup has — I mean, some of the best sink in baseball, especially last night. There’s not many changeups like that, that have the vertical movement that that pitch has right now. And he’s throwing a slider for a strike, and it’s a quality pitch. He’s throwing it for a strike almost whenever he wants.

“When you pair a whole lot of sink with a tall guy with a higher slot, the ball is pretty steep coming to the plate. So guys have to work hard to get under the ball. So there are a lot of ground balls. It allows him to pitch at the bottom of the zone and have some freedom there. And then when he mixes up, it kind of surprises them. So I think the delivery and his physicality and how tall he is helps.”

Cotham said the Phillies have worked hard to instill a belief in Sánchez that his stuff is good enough to pitch in the zone.

“It’s not, ‘Hey, we need you to dot down and away, and up and in, down and in, here and there,’” Cotham said. “It’s if you throw strikes — you’re going to be great. You are very good, and that’s how you become great. And he’s done that. He’s had time to practice that.”

» READ MORE: How 6-9 slugger Carlos De La Cruz has become an unlikely top prospect

It’s a simple mindset, but it’s a made a difference, especially for a pitcher like Sánchez, whose movement has made it difficult to locate his pitches at times. Another difference has been in how he plays catch. Like Taijuan Walker, Sánchez is trying to be more athletic.

“Don’t get caught up in using your delivery right away when you’re playing catch,” Cotham said. “Feel your hand. Feel the ball off your fingertips. It’s OK to throw the ball like an infielder for a couple or explore for a little bit. And then we’ll work into the delivery. So throw first, and we’ll pitch after that. He’s doing a nice job with that.”

But perhaps the biggest change has been in Sánchez’s resiliency. Cotham saw a change right away, from when Sánchez made his June 17 start in Oakland. In the fourth inning, he was hit by a comebacker off the bat of Esteury Ruiz but remained in the game. He walked his next batter to put runners on first and second. But Sánchez didn’t allow the A’s to build any momentum.

He struck out his next three batters to end the inning.

“It looked like he was on the brink of coming out of the game, and he settled in,” Cotham said. “You see that and realize that might have maybe gone differently two years ago.”