Lambert will be called up and make his MLB debut Thursday against the Cubs, Kyle Newman of The Denver Post reports.
Lambert was expected to be called up with Kyle Freeland getting sent to Triple-A Albuquerque, and Newman reports the 22-year-old right-hander has arrived at Wrigley Field and will take the hill Thursday for his big-league debut. He's on the club's taxi squad, so the callup should be made official ahead of Thursday's game, per MLB.com's Thomas Harding. Lambert is considered the Rockies' top pitching prospect, and given the club's starting rotation struggles this season, he has a chance to make a case to stay in the rotation with a good performance.