KANSAS CITY -- Rogers Centre in Toronto wasn't kind to Alejandro De Aza.

After playing on the turf at the home of the Blue Jays, De Aza developed a stiff back. He was lifted for a pinch-hitter in the eighth inning of Friday night's game against the Royals when the back began to cramp and wasn't in the lineup on Saturday. Dewayne Wise drew the start in center field.

Manager Robin Ventura will likely keep De Aza out of the lineup on Sunday as well.

"Dewayne has filled in great," Ventura said. "We'll probably give [De Aza] a couple of days."

De Aza had started 107 games in center field through Friday.

Trend-setter Humber reflects on no-hitters

KANSAS CITY -- Right-hander Philip Humber is a trend-setter.

When Humber pitched his perfect game on April 21, it triggered a flurry of pitching gems. Since Humber achieved perfection, there have been five no-hitters, including two perfect games. Seattle's Felix Hernandez was the latest to join the perfect-game club with his 27-up-27-down outing against Tampa Bay on Wednesday.

Six no-hitters and three perfect games with six weeks to go in the regular season? Humber has his theories as to why there have been so many no-hit masterpieces.

"Hitters today have a little bit different approach than they used to have," Humber said. "There's more emphasis on power, as opposed to contact. The strikeout is not looked at as such a negative for a hitter. A lot of guys are going up there looking for a pitch to drive, even with two strikes. They're not just looking to put the ball in play. The more times the ball is in play, the more chances you have to get a hit."

Humber also thinks that advanced video technology can help a pitcher or a combined staff gain the necessary information to stymie opponents over nine innings.

"The hitters study us, too," he said. "But the pitcher has the ball and knows that if he makes all the right pitches, this is how he can get a guy out. If a pitcher has all the information, great stuff and tremendous command on a given day, that's how a no-hitter or perfect game can happen."

Jered Weaver of the Angels followed Humber's perfect game with a no-hitter on May 2. Mets left-hander Johan Santana followed with a no-hitter on June 1, and six Seattle pitchers combined to no-hit the Dodgers a week later.

Then Matt Cain of the Giants and Hernandez added perfect games against the Astros and Rays, respectively.

"I'm sure it's cyclical, but when I threw my perfect game, only 20 guys had done it in Major League history," Humber said. "And now there have been two more in less than three months. It's pretty amazing, but that's part of the beauty of baseball. You never know what's going to happen."

Konerko set to play first base on Sunday

KANSAS CITY -- For the first time since Aug. 7, Paul Konerko is expected to play first base for the White Sox on Sunday.

Konerko, who has worked his way back from a concussion, was in the lineup as the designated hitter on Saturday for the second consecutive game. Manager Robin Ventura plans to use Konerko defensively in the series finale against the Royals.

"I just wanted to make sure he was acclimated," Ventura said.