Kilian is 2-0 with a 2.06 ERA in nine starts for Triple-A Iowa this season. He had 41 strikeouts in 39.1 innings before being called up.
Kilian was acquired with outfielder Alexander Canario last July 31 for Bryant as part of the Cubs roster tear down. He has a career 2.08 ERA in three minor league seasons after being drafted in the eighth round by the Giants in 2019.
To make room on the 40 man roster, the Cubs DFA’d pitcher Conner Menez. They also recalled righty Anderson Espinoza to serve as the team’s 27th man for the doubleheader. Killian will be the team’s eighth player to make his major league debut this season.