The Lions also re-signed long snapper Don Muhlbach and cornerback Crezdon Butler.
Contract terms were not disclosed.
The 32-year-old Orlovsky, entering his 11th NFL season, returns to Detroit after appearing in two games last season as Matthew Stafford's backup.
Originally drafted by the Lions in the fifth round of the 2005 NFL Draft out of Connecticut, Orlovsky played his first four years in the NFL with the Detroit Lions before spending time with the Houston Texans (2009-10), Indianapolis Colts (2011) and Tampa Bay Buccaneers (2012-13). He has appeared in 26 games (12 starts), completing 298 passes on 512 attempts for 3,132 yards and 15 touchdowns.
Whitehead, 25, rejoins the Lions following a 2015 season in which he saw action in all 16 games, including nine starts. He finished the season with 47 tackles, a career-high two sacks, one interception, one fumble recovery and a career-high six pass defenses. He began his career as a standout on special teams from 2012-13 before recording a career-high 77 tackles during the 2014 season. Detroit's fifth-round selection in the 2012 draft out of Temple, Whitehead has played in 62 career games (24 starts), missing only two games in 2012 as a rookie. His career totals include 124 tackles, two sacks, three interceptions, 11 pass defenses, two forced fumbles, one fumble recovery and 33 special teams tackles.
Muhlbach, 34, returns to Detroit entering his 13th season with the Lions. By playing in all 16 games in 2015, his 180 career games played currently rank eighth all-time in Lions history. He is just the 17th player in franchise history to play 12 seasons with the Lions.
Butler, 28, spent 2015 training camp with the Lions before rejoining the team as a free agent midway through the season. He appeared in the final eight games of the season and finished with three total tackles. A seven-year NFL veteran, Butler was drafted by the Pittsburgh Steelers in the fifth round of the 2010 draft. In 45 career games (three starts), he has 25 tackles and two forced fumbles.