Former New York Jets safety Adrian Colbert and veteran pass rusher Chris Smith visited the Texans, according to league sources not authorized to speak publicly.
Colbert played collegiately at Texas and Miami.
A former San Francisco 49ers seventh-round draft pick, Colbert has also played for the Seattle Seahawks, Miami Dolphins, Kansas City Chiefs, New York Giants, New England Patriots and Jets.
He played in four games with three starts for the Jets this season before being released.
He has 109 career tackles and two forced fumbles.
Smith, 29, is a 6-foot-1, 266-pound former Jacksonville Jaguars fifth-round draft pick from Arkansas who has also played for the Cincinnati Bengals, Cleveland Browns, Carolina Panthers and Las Vegas Raiders.
Smith had a career-high three sacks and 26 tackles in 2017 with the Bengals and 21 tackles.
He has 68 career tackles and 8 1/2 career sacks.