Dolphins sign veteran CB Mackensie Alexander, place Trill Williams on IR

The Dolphins have signed Mackensie Alexander, the team announced Monday, adding a veteran cornerback to a position group whose depth is being tested in training camp.

The team also announced the signing of defensive tackle Niles Scott and placed cornerback Trill Williams on injured reserve, ending the promising second-year player’s 2022 season.

Alexander, who turns 29 in November, started five games for the Minnesota Vikings in 2021, recording 51 combined tackles and five pass deflections. A second-round pick of the Vikings in the 2016 NFL Draft, Alexander has made 25 starts for the Vikings and Cincinnati Bengals, recording 201 tackles, three interceptions, 32 pass deflections and 4.5 sacks.

Alexander joins a position group whose depth has become more uncertain three weeks into training camp.

Williams, who was pushing to be the team’s No. 4 corner, tore his ACL tear in the team’s preseason-opening win over the Tampa Bay Buccaneers on Saturday night. Byron Jones remains on the physically unable to perform list after offseason Achilles surgery with less than a month to go until the team’s season opener against the New England Patriots on Sept. 11. Head coach Mike McDaniel said Jones is expecting to be available for Week 1.

Noah Igbinoghene and Keion Crossen are both top internal candidates to take up the key backup spot behind Jones, Xavien Howard and nickelback Nik Needham. Crossen, who has made four career starts in four seasons — all in 2020 — has had an impressive camp, while Igbinoghene, a 2020 first-round pick, has struggled with consistency. He was the closest defender on a 23-yard touchdown pass in Saturday night’s game.

The Dolphins also worked out former Baylor cornerback Raleigh Texada.

Scott, who turns 27 in September, most recently spent time on the Seattle Seahawks’ practice squad in 2021 and was waived in May. He went undrafted in 2018 and appeared in six games for the Bengals that season, recording four tackles.