Regarding Montgomery, this opens a three-week window of time for the Saints to activate him from injured reserve and add him to their 53-man roster.
Alonso, 29, is a former second-round pick of the Bills back in 2013. The Bills traded to the Eagles in return for RB LeSean McCoy back in 2015.
From there, Alonso was traded to the Dolphins along with Byron Maxwell back in 2016 in return for a first-round pick. Miami later traded him to the Saints for OLB Vince Biegel at the start of the 2019 season.
Alonso agreed to a restructured contract in March that will pay him a $1.7 million base salary and $1.45 million roster bonus that is fully guaranteed on the fifth day of the league year. He also gets $4.7 million in incentives that is dependent on playing time and being active for 10 or more games.
In 2019, Alonso appeared in 13 games for the Saints and recorded 31 tackles, no sacks or interceptions and one pass defense.
Montgomery, 27, is a former third-round pick of the Packers back in 2015. Green Bay traded him to the Ravens in exchange for a 2020 seventh-round pick back in October of 2018.
Montgomery finished the final year of his four-year, $2.949 million contract and before signing a one-year contract with the Jets last year.
The Saints signed him to a contract this past May.