Glennon, 29, is a former third-round pick of the Buccaneers back in 2013. He played out the final year of his four-year, $3.104 million rookie contract before signing a three-year, $45 million contract with the Bears in 2017.
The Bears elected to move on from him after just one season and he later signed a two-year $8 million contract with the Cardinals last year.
In 2018, Glennon appeared in two games for the Cardinals and threw for 174 yards while completing 71.4 percent of his passes and one touchdown.
Bethea, 34, is a former sixth-round pick of the Colts back in 2006. He spent eight years in Indianapolis before signing a four-year, $21 million contract with the 49ers back in 2014.
Bethea was set to make a base salary of $5.25 million for the 2017 season when the 49ers released him and he later signed a three-year, $12.75 million contract with the Cardinals in 2017.
In 2018, Bethea appeared in all 16 games for the Cardinals and recorded 121 tackles, three sacks, a forced fumble and four pass defenses.