The Chicago White Sox have spent the better part of a year rebuilding their farm system, and on Friday one of the crown jewels of that system will be on the mound at Guaranteed Rate Field.

The White Sox officially called up pitcher Reynaldo Lopez on Friday, paving the way for him to start Friday’s game against the Kansas City Royals. Lopez, acquired from the Washington Nationals in the Adam Eaton trade last winter, is one of the top prospects in the team’s system, and he will be looking to continue his strong play of late when he toes the rubber Friday.

Lopez has started 22 games for the Triple-A Charlotte Knights this season, going 6-7 with a 3.79 ERA and 131 strikeouts.

Outfielder David Holmberg was optioned to Charlotte to clear room on the team’s 25-man roster.

The White Sox are riding high after a three-game sweep over the AL West-leading Houston Astros this week. That series was capped off by Yoan Moncada’s first career home run as a member of the White Sox, and the rookie ended up driving in the game-winning run with a base-hit in extra innings.