"It's kind of like that blessing and curse of being versatile," Thornburg said. "You never really know what you're going to do, but you're always going to be doing something."
If all goes as planned for the Brewers, Thornburg would wind up back in the bullpen. If a need arises, he could help bolster a starting rotation that has five starters set (Kyle Lohse, Matt Garza, Wily Peralta, Mike Fiers and Jimmy Nelson), and is thin beyond that.
"If something happens -- and hopefully it won't -- to our five guys, he's a guy who could step in and start for us," Roenicke said.
Most importantly, Thornburg said, his elbow feels "great." He was among the Brewers pitchers who threw a bullpen session on Tuesday.
"Honestly, I'm a little nervous/excited to see how the games are, just because I've been out of it so long," Thornburg said. "I don't think anything is going to be any different."
Once considered the Brewers' top prospect, Thornburg owns a 3.04 ERA over parts of three years in every imaginable role. He began last season as the bullpen's long man, but quickly ascended up the depth chart to seventh- and eighth-inning duties. In one stretch before his elbow gave out, Thornburg retired 21 consecutive batters.
He's said before that his preference remains to start. But Thornburg's willingness to assume whatever role will keep him in the big leagues earned praise from Roenicke.
"Eventually, I kind of want to do one thing, because I feel like if I had the ability to concentrate on one thing, I could do very, very well at it," Thornburg said. "Not to say that bouncing around I haven't done well. You never know what's going to happen next year. You never know what's going to happen a week into the season. Things play themselves out."
Adam McCalvy is a reporter for MLB.com. Read his blog, Brew Beat, and follow him on Twitter at @AdamMcCalvy. This story was not subject to the approval of Major League Baseball or its clubs.