The deal was announced by the Seahawks on Monday.
Sims was Seattle's fourth-round pick in the 2006 draft and started 34 of 45 games played in his four seasons with the Seahawks. Sims started all 14 games he played in last season at left guard.
Henderson was a sixth-round pick of the New York Giants in 2008 and signed with Detroit as a free agent. He spent the season on the Lions practice squad.
Information from The Associated Press was used in this report.