Maurer agreed to a minor-league contract with the PIrates on Wednesday, Jon Heyman of FancredSports.com reports.
Maurer is coming off a difficult season in Kansas City, where he struggled to an ugly 7.76 ERA in 31.1 innings. The 28-year-old didn't fare much better with Triple-A Omaha, throwing 23 innings with an ERA of 5.48.