Martinez has been a bench coach since 2008, first starting with the Tampa Bay Rays on Joe Maddon's staff. Martinez followed Maddon to Chicago after he took the Cubs job at the end of the 2014 season.
According to the report, Martinez will be announced as the manager after the completion of the World Series. The Nationals and Martinez agreed to a three-year agreement with an option for 2021, reports Chelsea Janes of the Washington Post,
Martinez, 53, played in the major leagues 16 years before retiring in 2001.
Martinez will replace Dusty Baker, who was fired after two seasons with the team.
The Nationals won the NL East by 20 games this season, but were ousted in five games in the National League Division Series by the Los Angeles Dodgers.