Tyler Colvin made his major league debut at first base for the Cubs on Tuesday against the Diamondbacks. He replaced Carlos Pena, who is dealing with a sprained right thumb. Pena suffered the injury during Monday's 4-1 victory over the Diamondbacks on a play to his far right. "I actually made the play in the seventh on a ball into the hole," Pena said. "As I threw the ball, I put my glove hand down and kind of jammed it into the ground."