(SPRINGDALE, Ark., AP) — The Northwest Arkansas Naturals have announced a four-year extension of the club’s player development agreement with the defending World Series champion Kansas City Royals.

The agreement announced Monday means the Naturals will remain the Royals Double-A affiliate through the 2020 season.

The Naturals play in the Texas League and have been the Royals affiliate since moving to Springdale in 2008.

Northwest Arkansas opens the 2016 season on Thursday by hosting the Frisco RoughRiders.