Flacco was 3-for-5 passing for 28 yards and played one series in Sunday's preseason loss to Denver.
Flacco should get more work later in the preseason as the backup to Anthony Richardson. The reigning NFL Comeback Player of the Year is coming off an impressive showing with Cleveland last season but will be strictly a backup in Indy. He gives the Colts a veteran capable of keeping the team afloat should Richardson go down.