Mattheus agreed to a minor league contract with the Reds on Friday that includes an invite to spring training, C. Trent Rosecrans of the Cincinnati Enquirer reports.
Cincinnati declined to tender Mattheus a contract at the end of the 2015 season, but will welcome the right-hander back on a minors deal with a chance to earn a bullpen spot in the spring. Mattheus does not have the swing-and-miss stuff to replace Aroldis Chapman as the Reds' closer (career 5.3 K/9), but he generates groundballs at a good clip and lowered his walk rate back below 3.0 BB/9 last season.