Sources told Jeff Passan on Saturday that George Kirby, one of the best pitching prospects in baseball, is going to be called up by Seattle.

Kirby, who was scratched from his start for Double-A Arkansas on Saturday, will be making his major league debut for the SeattleMariners on Sunday.

The plan was for Matt Brash to be a relief pitcher for the rest of the season after he was optioned to Triple-A.

Kirby, who was the 20th overall pick in the MLB draft, has a huge ceiling with excellent command and above-average stuff, including his fastball, which averaged 97.3 mph over the 2021 season.

He has been called an "robopitcher" by some Mariners brass because of his excellent control.

Kirby has excelled in his five starts in the Double-A Texas League this season, going 2-0 with a 1.82 earned run average and 24 strikeouts. He could provide a boost for the team, who are in the midst of playing 16 games in 16 days.

He was ranked as a prospect to watch by ESPN.

In five starts, Brash was 1-3 with a 7.65 ERA.

Tom Murphy was placed on the injured list with a shoulder injury and Cal Raleigh was recalled from Triple-A.

Murphy is batting.303 with a home run and nine runs scored in 14 games this season.

The report was contributed to by Kiley McDaniel.