The Astros informed Lambert on Sunday that he won't be included on the Opening Day roster, Chandler Rome of The Athletic reports.
Lambert had attended spring training as a non-roster invitee but made a spirited bid for a spot in Houston's bullpen by turning in a 2.92 ERA and 8:5 K:BB in 12.1 innings during the Grapefruit League. The right-hander's minor-league contract contains an opt-out clause that will allow him to pursue opportunities elsewhere, but Lambert is still deciding whether to become a free agent or stay in the organization and report to Triple-A Sugar Land, per Rome.