Manuel, 28, is a former first-round pick by the Bills back in 2013. He played out the final year of his four-year, $8,885,300 rookie contract but the Bills declined to pick up his fifth-year option for the 2017 season.
Manuel signed back-to-back one-year contracts with the Raiders but was waived coming out of the preseason last year.
In 2017, Manuel appeared in two games for the Raiders and completed 55.8 percent of his passes for 265 yards to go along with one touchdown and one interception.
Coates, 25, is a former third-round pick of the Steelers back in 2015. He’s currently in the final year of his four-year, $3 million contract and set to make a base salary of $705,000 for the 2017 season.
The Steelers traded Coates to the Browns last year for a 2018 sixth-round pick. Cleveland elected to waive Coates back in March and he was later claimed by the Texans. Houston cut him loose last month.
Since becoming a free agent, Coates worked out for the Cowboys but was not signed to a contract following the session.
In 2018, Coates appeared in 12 games for the Texans and caught one pass for 12 yards receiving and no touchdowns.