In an attempt to continue the overhaul of their beleaguered bullpen, the Mets are expected to sign right-handed pitcher Brandon Lyon, according to a person familiar with the matter. The deal should be finalized this week, making Lyon the third free-agent reliever the Mets have acquired in recent days, along with Scott Atchison and LaTroy Hawkins. Lyon, 33 years old, appeared in 67 games last season for the Houston Astros and Toronto Blue Jays, going 4-2 with a 3.10 earned-run average across both leagues.