Chicago Cubs first baseman Derrek Lee, who leads the majors with a .378 batting average, left Tuesday night's game against the Atlanta Braves with a shoulder injury. Lee backed out of the batter's box in apparent pain during his first-inning at-bat. He remained in the game and struck out. After playing two innings, however, Lee left the game. Manager Dusty Baker said Lee left with left shoulder irritation. "The shoulder has been bothering him off-and-on for a little while," Baker said. "He took a swing tonight and aggravated it." Baker said Lee will be examined Wednesday by Braves team orthopedic specialist Dr. Joe Chandler. Lee had declined an invitation to participate in the Home Run Derby because of lingering soreness in his shoulder, according to MLB.com Lee is second in the majors with 25 homers and third in the NL with 67 RBI.