Don Mattingly and the rebuilding Miami Marlins have agreed to a contract extension, a source told ESPN, confirming an El Extrabase report.

Mattingly will receive a two-year deal from the team, a source told ESPN's Jeff Passan, confirming an MLB Network report. An official announcement is expected Friday, when Miami opens a three-game series against the visiting Nationals before finishing the season on a seven-game road trip.

Mattingly initially signed a four-year contract with the Marlins prior to the 2016 season. He is a career 272-364 with the team.

The 58-year-old Mattingly will be the first to manage the Marlins for more than four seasons.

Under new part-owner/CEO Derek Jeter, the Marlins have been in rebuilding mode, trading away key pieces in recent seasons such as Christian Yelich, Giancarlo Stanton, J.T. Realmuto and Marcell Ozuna. They are an NL-worst 53-99 this season.