The White Sox maintained their hold on first place in the American League Central with an 8-2 victory over the Royals at Kauffman Stadium on Sunday. They completed a four-game road sweep of Kansas City and finished the season at 9-1 against the last-place team in the division.

• Box score

But the more concerning White Sox story after the team’s 16th win in its last 20 games centered upon starting pitcher Dallas Keuchel, who exited with lower back stiffness after warming up for the sixth inning and looking to be in some discomfort after throwing his final warmup pitch to catcher Yasmani Grandal. Keuchel allowed only two hits and struck out two, needing a mere 49 pitches to complete his work.

He is day to day, per the club. Keuchel tweaked his back fielding a comebacker from Cam Gallager to end the fifth and said he alerted the coaching staff. It’s an issue the veteran southpaw has dealt with for much of the season.

“It's just one of those things, man,” Keuchel said. “I don't really like to talk about nagging injuries or this or that, just because I don't want anyone to feel sorry for me. I'm not going to make excuses or anything like that. Just talking about it in general kind of frustrates me. It pops up every once in a while.

“I'm going around the field more than other pitchers, so it kind of hinders my ability to stop and just be a pitcher and not let my athletic ability take over and make some plays that I normally should.”

Keuchel left his last start against the Twins after five innings due to stomach discomfort. But in the four days leading up to Sunday’s outing, Keuchel said his back felt as good as it had in a long time.

“Hopefully tomorrow I can wake up and maybe be a little sore,” Keuchel said. “But knowing that I have an off-day tomorrow and not pitch until Saturday, it will hopefully work out.”

Among his four RBIs in the win, Edwin Encarnación hit a three-run home run in the seventh, following a walk issued to Grandal and José Abreu’s single to center field. Abreu has hit in 20 straight games, leaving him one short of matching his career-high of 21 from 2014 and nine short of surpassing Carlos Lee’s club record of 28 from 2004.

Yolmer Sánchez made the most of a spot start at third base with two doubles, two walks and two runs scored. Sánchez played the first six years of his career with the White Sox and then returned as a free agent on Aug. 28, after the Giants released him the week prior.

“We’ve been talking since last year and this was the best option, so that’s why I came back. And it definitely helps that you know everybody here,” Sánchez said. “It feels like home. It was an easy decision.”

The setback with Keuchel -- albeit possibly a short-term issue -- adds to a White Sox starting rotation beset by physical problems. Carlos Rodón had back discomfort that prevented him from throwing 60 pitches Friday at the team’s alternate training site in Schaumburg, Ill. Rodón is on the 10-day injured list with left shoulder soreness.

Gio González is also on the IL with a right groin strain, while Reynaldo López -- who was on the IL with right shoulder soreness after his first start of the season -- was sent back to Schaumburg after his last start against the Twins to work on finding more consistency. Dylan Cease and Dane Dunning are healthy, but they also are young pitchers being pushed into the heart of a playoff run.

The White Sox still hold a half-game lead over the Indians and a 1 1/2-game advantage over the Twins. Keuchel and manager Rick Renteria hope he’ll be ready to go the next time his name is called. 

“Any time you have a health issue that can linger, it’s always something you are aware of,” Renteria said. “I’m more of an optimist than a pessimist. I’ll deal with the issues that present themselves when they present themselves. At this point, I’m not worried. We are going to continue to play and do what we do.”

“This is not the worst it's been,” Keuchel said. “I don't really do much tomorrow anyway in my routine. It would just be my cardio session to get loose and a bunch of mobility stuff to stretch out. I'm pretty sure I'll be able to do my cardio and hopefully stretch this thing out and see where we're at tomorrow.”