Newman signed a one-year, $3 million deal and enters his 14th season. He previously played under head coach Mike Zimmer while they were together with the Dallas Cowboys and Cincinnati Bengals -- Zimmer was an assistant coach for both teams before he was hired by the Vikings in 2014.
He has 40 career interceptions and was a first-round pick (fifth overall) of the Cowboys out of Kansas State in 2003.
Sherels visited the New York Jets last week but accepted a deal with the Vikings on Tuesday.
Undrafted out of the University of Minnesota, Sherels plays cornerback but his greater impact has been as the team's primary punt returner. He had a return for a touchdown against the Chicago Bears last season at Soldier Field, a 65-yarder that helped Minnesota win a one-score game.
Ellison is a block-first tight end who had 11 receptions for 124 yards and a touchdown last season. A fourth-round pick in 2012, he has played in 58 career games with the Vikings, including 35 starts. Ellison has 42 career catches and three touchdowns.