Vallos (6-foot-3, 310 pounds) is a veteran of six NFL seasons and has 59 games of NFL experience.
Adams (6-5, 250 pounds) entered the NFL as a undrafted free agent who originally signed with the Jacksonville Jaguars.
---The Pittsburgh Steelers signed running back Stephen Houston.
Houston entered the NFL as an undrafted free agent with the New England Patriots following the 2014 draft. The 6-foot-0, 230-pound Indiana product finished fourth on the school's all-time list with 25 rushing touchdowns.
---The New Orleans Saints signed tight end Travis Beckum.
The 6-foot-3, 234-pound Beckum was originally a third-round draft pick of the New York Giants in 2009 out of Wisconsin. In four NFL seasons from 2009-12, Beckum appeared in 48 career games with the Giants with four starts and recorded 26 receptions for 264 yards with three touchdowns.
The Saints also officially placed tight end Richard Quinn on the reserve/retired list.
---Philadelphia Eagles wide receiver Jeremy Maclin left practice with a hamstring strain.
Maclin was in the middle of an impressive individual display, getting behind New England Patriots cornerback Darrelle Revis on multiple occasions in the second day of joint practices.
Maclin said his left hamstring "grabbed" but thought he would be ready for Friday's preseason game.
---The Jacksonville Jaguars signed fifth-year center Antoine Caldwell and waived/injured Matt Stankiewitch (wrist).
Caldwell was originally a third-round selection by the Houston Texans in the 2009 draft. Caldwell (6-foot-3, 315 pounds) was with the Jaguars in mid-May on a tryout basis for the team's rookie minicamp, but he was not offered a contract.