Clint Hurdle will return to manage the Pirates in 2018, according to sources with knowledge of the situation.

Hurdle has agreed to a four-year contract extension, which replaces the 2018 club option on his current deal and keeps him under contractual control through 2021.

The guaranteed portion of Hurdle’s current contract, agreed to in April 2014, expires at the end of this season. The Pirates have not announced the move.

Hurdle, 60, took over the Pirates in 2011 and has a 574-534 record in seven seasons. The team reached the playoffs for three consecutive years, from 2013-15, but only in ’13 did it advance further than the National League wild-card game.