Nelson will serve as the Diamondbacks' opening pitcher Sunday against the Phillies, Nick Piecoro of The Arizona Republic reports.

EDGE Analysis

By tapping the left-handed Nelson, Diamondbacks manager Torey Lovullo hopes to neutralize sluggers Kyle Schwarber and Bryce Harper, lefty hitters at the top of the Phillies' order. Nelson is not expected to go much more than an inning. Luke Weaver, who Arizona added to its taxi squad Saturday, is expected to pitch multiple innings following Nelson. The need for a fill-in starter was created when Humberto Castellanos (elbow) was added to the 15-day injured list.