Contreras now has 21 homers, and is tied with Anthony Rizzo for the team lead with 70 RBIs. Contreras also is tied with Miami's Giancarlo Stanton for most home runs since the All-Star break with 10.
"I can't believe it, to be honest," Contreras said. "I can't believe it. To be able to put a good swing on a fastball and good pitches -- I'm not out there trying to hit homers. I'm trying to put the barrel on the ball, and it just goes."
Since June 16, Contreras is batting .331 with 16 homers and 45 RBIs in 42 games. He's the first Cubs catcher to reach 20 home runs in a season since Geovany Soto hit 23 in 2008, when he won National League Rookie of the Year honors.
In six games this week, Contreras is batting .455 (10-for-22) with five homers and 13 RBIs. He also hit two home runs and drove in a career-high six runs on Thursday against the Diamondbacks.
Asked to assess Contreras' week, Rizzo just shook his head.
"Incredible," Rizzo said.
Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.