San Diego Padres first baseman Yonder Alonso is not in the lineup Sunday against the Colorado Rockies because of a head injury, according to the team's official website. Alonso was lifted late in Saturday's game and subjected to concussion testing after outfielder Justin Upton accidentally hit him in the head with a batting helmet in the dugout. Upton was walking in the dugout and attempted to throw his helmet on the ground in frustration, only for it to leave his hand early and hit Alonso right on the head. It is unclear if Alonso was suffering from concussion symptoms, and it is possible that he is not playing Sunday as a precaution. Derek Norris will get the start at first base in place of Alonso, who is hitting .271 with four home runs and 27 RBI in 89 games this season.