Nelson (elbow) will begin a rehab assignment with Low-A Wisconsin on Sunday, Todd Rosiak of the Milwaukee Journal Sentinel reports.
Nelson is having a rough season after missing all of 2018 for shoulder surgery. He owns an 8.36 ERA, a 2.29 WHIP and a 15:14 K:BB in 14 big-league innings. He's been out with a right elbow effusion since late June and will fill a relief role once he's cleared to return to Milwaukee.