CHICAGO -- White Sox right-hander Michael Kopech threw a season-low four innings and a season-low 86 pitches during a 6-3 loss to the Rangers Wednesday night at Guaranteed Rate Field, with the American League West leaders winning the series.

But the reason for Kopech’s early departure, with his team trailing, 3-1, at the time, was not because of any sort of physical ailment. It was more of a season-long load management for the young hurler. Kopech understood manager Pedro Grifol’s line of thought.

“Yeah, I feel alright,” said Kopech after receiving treatment postgame. “More so, just [frustrated], a little bit about how I’ve been pitching. I know what this team needs and I know I’ve been not giving that. To not be getting more than five innings per start, especially in my last few, it’s embarrassing to say the least.”

On June 10 against Miami at home, Kopech threw five scoreless innings and struck out six, throwing 100 pitches. He followed up that start on June 16 in Seattle by walking six over 4 1/3 innings, while allowing just one run, but needing 102 pitches.

Despite going to four three-ball counts in the first two innings Wednesday, it was the third and fourth when the Rangers (46-28) got to Kopech (3-6) for three runs, punctuated by Ezequiel Duran’s two-run homer in the fourth.

“If we didn’t have a day off tomorrow and if we didn’t have some length back there, I probably would have let him go back out,” Grifol said. “But he’s thrown a lot. He’s made every start but one. Just gave him a couple of days extra. I think all these guys at some point need a little bit of a break.”

“I didn’t have it today. He saw that,” said Kopech, who struck out five and walked three. “We are looking for wins right now. To not be in a position to do my best to help the team win is a tough pill to swallow.”

That early departure gave way to Jimmy Lambert, who allowed Jonah Heim’s three-run homer in the fifth. Heim's dinger came on a 2-2 count after a 1-2 changeup that clipped the zone per Statcast was called ball 2. Then, it was time for Touki Toussaint to take over.

Toussaint threw four hitless innings in his White Sox debut, walking two, in an outing to be remembered for more than just his success. His flight out of Miami was delayed two hours, and he then received a true welcome to Chicago by dealing with rush hour traffic on the Kennedy Expressway.

After arriving at the ballpark at 6 p.m. CT, all Toussaint knew was that he was going to pitch Wednesday.

“It’s been a whirlwind this last week,” said Toussaint, who was designated for assignment by the Guardians Saturday and claimed by the White Sox Tuesday (his 27th birthday). “They told me to be ready to pitch.”

Andrew Vaughn’s 11th home run was the biggest connection off Texas starter Martín Pérez over seven innings, on a night when White Sox shortstop Elvis Andrus played his 2,000th career game. The loss dropped the White Sox to 32-44 and 7-16-1 in series play (the club's fourth straight series loss), and they lost ground to Minnesota, Cleveland and Detroit ahead of them in the American League Central.

Those standings really don’t matter, though, if the White Sox ultimately don’t play better. It’s a sentiment Kopech echoed individually with an eye to his next start in Anaheim.

“I’ll be better,” Kopech said. “I mean, there’s a bigger thought-process to this season. I can appreciate what [Grifol] has to say, keeping me resting and everything.

“As a competitor, I wanted it. As a part of this team, I knew I didn’t have it today. So, I did understand the move. Just wanted to be better. He saw a bigger picture and I can appreciate that.”