Peterson aggravated his thumb injury and has been informed he won't make the Opening Day roster, Tom Haudricourt of the Milwaukee Journal Sentinel reports.
The 30-year-old dealt with the thumb issue earlier in spring training, and the issue has resurfaced since he returned to action March 10. Peterson is in camp as a non-roster invitee and will focus on getting healthy in hope of an early-season promotion after failing to make the Opening Day roster.