Peterson will be reuniting with Brewers manager Ken Macha (the two were together in Oakland) and bench coach Willie Randolph (they were together in New York). Peterson has an especially close relationship with Randolph. Peterson and Macha had some differences of opinion in Oakland, but they have reconciled.
The Brewers were 15th in the National League with a 4.83 ERA this season.
Peterson is a statistical expert who oversaw the emergence of Barry Zito in Oakland. He and Randolph were fired by the Mets in the midnight massacre in June of 2008.