WASHINGTON -- As much as it pains him, Lucas Giolito won’t get the chance to pitch against his former team -- at least this season. “That would have been nice,” he said before the White Sox opened a two-game set against the Nationals on Tuesday. “Whenever you get to face

WASHINGTON -- As much as it pains him, Lucas Giolito won’t get the chance to pitch against his former team -- at least this season.

“That would have been nice,” he said before the White Sox opened a two-game set against the Nationals on Tuesday. “Whenever you get to face an old team, you always have that little bit of extra fire going in. I got a little bit of that in Triple-A a couple years ago when I was on Charlotte against Syracuse. But doing it at the big leagues, that’s the best. So maybe in a couple years or whenever it happens again.”

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But if it was any consolation, he was excited to see teammate Reynaldo López get the chance to do what he couldn’t Tuesday night after both hurlers -- along with Chicago’s No. 6 prospect Dane Dunning -- were acquired from Washington in exchange for Adam Eaton in 2016.

Lopez, however, had a rocky start in his return to Nationals Park -- a 9-5 loss that dropped the White Sox two games under .500. It was the first chance that either Lopez or Giolito had to face off against their old club, the first chance to pitch in Washington -- and the first chance either of them had to show their old club what it was missing out on.

Unfortunately for Lopez, things did not go as he had hoped. Despite being staked to a 4-0 lead before he even took the mound, Lopez watched that advantage slip away while allowing six runs over four-plus innings.

"It wasn't a factor in the outcome of the game,” Lopez said through a translator, downplaying the impact of nostalgia playing in his old stomping grounds.

"It was nice to come back to this ballpark and to face this organization, especially because it was the organization that gave me the opportunity to play professionally and to play in the Majors,” he added. “I still have a few friends on the other team. … It's a nice feeling just to come back and to see them and to face them."

Lopez struggled to find his groove in front of his former teammates Tuesday. He has had trouble building off an encouraging 2018 season in which he had a 3.91 ERA at just 24 years old.

The righty has now allowed at least five earned runs in each of his past three starts, ballooning his ERA from 5.14 to 6.62 over that span. He has nearly as many walks (10) over his last four starts as strikeouts (11), and his strikeout-to-walk ratio now sits at 1.88 in 2019.

“[We’ve tried] to break it down, covering both sides of it, both the physical and the mental aspect of it,” manager Rick Renteria said. “Right now he seems to be in a little bit of a twilight zone.”

Tuesday was perhaps another tough reminder that Lopez is still just 25. He and Giolito, who is only 24 himself, have had their fair share of struggles throughout their respective careers, but each has shown flashes of brilliance as well. As Giolito admitted Tuesday, both have developed immensely since their time in D.C., but both believe they still have plenty to improve upon.

“He’s still not quite where he was as we’ve all seen him in the past -- how he finished, and went through the adjustments last season,” Renteria said of Lopez. “We’re still trying to get him back to that point again. And once we do that -- once he puts himself back in that situation -- you have an excellent starting pitcher. And he’s going to be an excellent starting pitcher.”

Lopez said he wasn’t aggressive enough with his pitches -- especially his breaking balls, one of which resulted in Anthony Rendon’s three-run homer to end his night before an out was recorded in the fifth.

“It may be that I'm not having a good feel for a few pitches,” Lopez said. “That was probably the case today. I've been feeling good. I am physically good. I am pretty close to turning things around and starting to get better and having better results.

“These bad stretches have been more about I've been thinking a lot,” he added. “As soon as I can clear my mind, and start thinking less and executing better pitches, things are going to turn around.”

But unfortunately for Lopez, he, like Giolito, is slated to pitch in the upcoming series in Kansas City, meaning he isn't scheduled to get a chance at some redemption when the Nationals come to Chicago for a pair of games next week.