"It's unexpected just because [Gamel has] gone through this period of time where he really hasn't had any issues with it," Roenicke said. "But probably not unexpected because it is different once you get on the field and now you're doing different exercises with agilities, with fundamentals. You're doing different things on the knee that you're not doing in a controlled environment."
Roenicke said Gamel first felt something in his knee while stretching, then felt it again while swinging the bat. Gamel conferred with a member of the club's athletic training staff and was taken back to the clubhouse for examination.
Does it qualify as a red flag?
"No, not now," Roenicke said. "I mean, if it happens a few times as we're going along, yeah."
Should Gamel experience more trouble with the knee, the Brewers may have to find someone else to mind first base while Hart also recovers. Options in camp include Alex Gonzalez, Taylor Green, nonroster invitee Bobby Crosby and prospect Hunter Morris.
Morris, 24, has yet to take a swing above Triple-A, but Roenicke did not rule him out.
"It would be pushing him, but say he comes out in Spring Training and he just goes off?" Roenicke said. "I don't know. He had some kind of year in Double-A, and that's where [shortstop Jean] Segura came from."
The Brewers brought in another first baseman, 2009 Draft pick Sean Halton, to cover Gamel's absence in Sunday's drills. Halton could remain for a few days.