The Diamondbacks have signed infielder Nicky Lopez to a minor league deal, assigning him to the Triple-A Reno Aces. Lopez, 30, has had a tumultuous year, with stints at the Cubs and Angels before returning to free agency, posting a poor .042/.179/.042 line in 28 plate appearances this season. Despite his offensive struggles, he brings defensive value with over 2,000 innings at middle infield positions, replacing Ildemaro Vargas, who opted out of his minor league deal.