The Diamondbacks reinstated Nelson (shoulder) from the 15-day injured list Thursday, Alex Weiner of ArizonaSports.com reports
Nelson threw 28 pitches in his second bullpen session Tuesday following his first session of 16 pitches. With his return coming near the close of the season, it seems Nelson will be used as a multi-inning reliever, but it is possible he may return as a starter. Yilber Diaz and Blake Walston were both optioned to Triple-A Reno on Thursday as part of a corresponding move.