"It's something I've worked for for a long time," Nelson said. "It still hasn't hit me."
He went 10-10 with a 3.25 ERA in 27 starts between Double-A Huntsville and Triple-A Nashville, plus a scoreless inning at the SiriusXM All-Star Futures Game in New York. Nelson's 3.8 walks per nine innings were a career-best, and his 9.6 strikeouts per nine innings were his best since Rookie ball in 2010, when the Brewers made Nelson their second-round pick in the First-Year Player Draft.
The Brewers have their starting rotation mapped out through the end of the season, and Nelson is not ticketed for a start, said manager Ron Roenicke, who stressed that every plan is subject to change.
"We already have six [starters]," Roenicke said. "There's just too many guys. With [Tyler] Thornburg, because he's pitched so well, we feel we need to see him in a starting role, and it's already a mess going to six guys. It's just a matter of, you're wanting to see guys, but you also want to give the guys you're looking at the opportunity to pitch well."
Nelson's last Triple-A start was Friday, so Roenicke planned to avoid using him Tuesday. On Wednesday, Nelson would be available for his first regular-season relief appearance since May 17, 2011, at Class A Wisconsin.
"It's just an adjustment," Nelson said. "I threw out of the bullpen a few times [at the University of Alabama] and I did it in the Fall League this last fall, so I've gotten a little taste of it. It's just an adjustment, a change in the mentality from starting to bullpen."
Nelson has already logged a career-high 152 1/3 regular season innings, but said he wasn't tired.
"If you're tired when you get called up, then you're not tired," he joked. "It's a little energizing. I felt good this year."
Adam McCalvy is a reporter for MLB.com. Read his blog, Brew Beat, and follow him on Twitter at @AdamMcCalvy. Kevin Massoth is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.