Gabbert, 28, made five starts last season with the Arizona Cardinals, finishing 95 of 171 for 1,086 yards with six touchdowns and six interceptions. He went 2-3 in his starts for the Cardinals, beating Tennessee in one of his wins.
A first-round draft pick (No. 10 overall) of Jacksonville in 2011, Gabbert endured three rocky seasons with the Jaguars, going 5-22 as a starter.
Gabbert resuscitated his career with the San Francisco 49ers in 2015, starting the final eight games and tossing 10 scoring passes versus seven picks while completing a personal-best 63.1 percent of his passes.
Like Mariota, Gabbert can be a threat with his legs, rushing for 440 yards in 18 games over the past three seasons.