Cubs OF Jason Heyward leaves game due to lightheadedness

CHICAGO -- Cubs outfielder Jason Heyward left Sunday's game against the St. Louis Cardinals because of lightheadedness and shortness of breath, according to manager David Ross. The team sent him to the hospital for further tests.

"He said he felt a little lightheaded after his first at-bat," Ross said following the Cubs' 7-3 loss. "He's not a guy you ever have concerns about, so when he says he's having trouble breathing and is lightheaded, you want to make sure everything is all right."

Heyward went 0-for-2 with a strikeout before being removed from the game.

Ross said Monday that Heyward was feeling better but there was no diagnosis yet. Heyward will not play in Monday's game against the Cardinals, Ross said.

Heyward, 31, has been one of the better hitters on the Cubs this season while playing solidly in right field.

"None of us know to what extent or how serious, but he's a big loss, not only with how well he's playing but also [being] a leader in the dugout," teammate Jason Kipnis said. "We're all concerned."