Nelson is expected to be added to the Yankees' 30-man roster Sunday.
Nelson was unable to secure a place on the Opening Day roster at summer camp, but he'll join the big club for the third game of the season. The 24-year-old posted a 4.71 ERA, 1.29 WHIP and 24:7 K:BB over 21 innings (four starts) at Triple-A Scranton/Wilkes-Barre last season.