Heyward suffered a contusion on the right side of his rib cage after he caught Denard Span's fly ball and then slid into the wall. General manager Jed Hoyer said the team "dodged a bullet" because Heyward did not need to miss significant time.
"He was ready to come in the game [on Monday]," manager Joe Maddon said. "He was adamant that he could have done something for us last night. There's no reason to wait any longer. The trainers felt pretty good about it also."
On Monday, Heyward took batting practice for the first time since the crash. He did take advantage of the short break to work on his hitting stroke. Heyward hit his first home run on May 17 and was batting .225 overall.
Maddon said the lineup is whole again with Heyward back.
"He gets on base a lot and he plays great defense, and it permits [Ben Zobrist] to hit behind [Anthony Rizzo]," Maddon said. "It's the butterfly effect. They flutter their wings, and something else occurs. ... There's all these different moments that occur that we don't really recognize, because we don't see the obvious.
"He's not hitting .300, so obviously, people think he's not playing well, which is so far from the truth. He makes a great impact by his presence, he's a great defender, he gets on base a lot and he permits us to reorganize the batting order."
Heyward is not under orders to avoid diving for balls, though he knows he'll probably feel some discomfort if he does.
"Go play -- that's what I want to be able to do, get out there and go play and do everything I can on the field and not worry about it," Heyward 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.