Wada, who was making his 10th start for the Cubs, threw two pitches to Vance Worley before athletic trainer Ed Halbur went to the mound. He was joined by catcher John Baker, pitching coach Chris Bosio and manager Rick Renteria. After consulting with Wada, the pitcher was then pulled from the game.
The Cubs said Wada had mild left calf cramping. The weather may have been a factor, as it was a steamy 88 degrees and very humid at Wrigley Field.
"I believe [the heat was the problem]," Wada said. "This was something I experienced in Japan in the past as well, so I felt it kind of came up again."
Wada hit two batters in a row in the third inning, and he said that's when he first experienced the cramp in his leg.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.