Holden, 25, is a former fifth-round pick by the Cardinals in the 2017 NFL Draft out of Vanderbilt. He spent one season with Arizona but was among their final roster cuts last year.
He bounced on and off the Colts’ and Saints’ practice squads before re-signing with the Cardinals in November of 2018.
In 2018, Holden appeared in four games for the Cardinals.
Allen, 29, is a former third-round pick of the Colts back in 2012. He signed a four-year, $29.4 million contract that included $16 million with the Colts in 2016 before he was traded to the Patriots for the 2017 season.
The Patriots elected to release Allen in March. The Dolphins signed him for two years and $7 million.
In 2018, Allen appeared in 13 games for the Patriots and caught just three passes for 27 yards receiving and no touchdowns.
Tankersley, 25, is a former third-round pick of the Dolphins back in 2017. He’s currently in the third year of a four-year, $3.17 million contract and set to make base salaries of $583,000 and $673,000 over the next two years of the agreement.
In 2018, Tankersley appeared in six games for the Dolphins and recorded five tackles and no sacks or interceptions.
Hull, 27, signed on with the Dolphins as an undrafted free agent out of Penn State back in 2015. He was among the Dolphins’ final roster cuts coming out of the preseason but was later added to their practice squad.
Since then, Hull has returned to the Dolphins on one-year, exclusive rights contracts. Miami placed him on injured reserve at the start of the 2018 regular season, but he later returned to the field.
Hull re-signed in Miami this March on a one-year deal.
In 2018, Hull appeared in eight games for the Dolphins, recording seven total tackles.