The Vikings earnestly began their effort to address their tenuous salary cap situation as the NFL's free agency negotiating window opened Monday, with a series of widely expected moves that netted them an extra $4.93 million in cap space, and they used some of that space to add to their defensive line.

The highest draft pick of the Mike Zimmer era, meanwhile, appeared set to bolt for the big city.

Linebacker Anthony Barr reportedly agreed to a deal with the New York Jets, where he'd likely get a chance to work primarily as a pass rusher after being used in a variety of roles during five seasons with the Vikings.

Barr, the No. 9 pick in the 2014 draft, made four Pro Bowls as a key piece of Zimmer's defense, but he fell short of delivering the kind of consistent dominance that could have earned him a long-term deal in Minnesota. He watched as defensive teammates Harrison Smith, Everson Griffen, Linval Joseph, Xavier Rhodes, Eric Kendricks and Danielle Hunter received new deals, and played out his fifth-year option as it became apparent he wouldn't return.

In addition to Barr leaving, the team saved $5.5 million by declining a 2019 option on safety Andrew Sendejo, and freed up $4.55 million by releasing guard Mike Remmers.

The Vikings used a portion of that space to place restricted free agent tenders on safety Anthony Harris and tackle Rashod Hill; Harris received a second-round tender that would be worth $3.095 million if he signs it, while Hill's tender is worth $2.025 million. The Vikings can match any offer given to either player, though they would not receive draft pick compensation for Hill, a former undrafted free agent given an original-round tender.

The Vikings' only move with a free agent from another team came in the form of a deal for a familiar face. According to an NFL source, the team plans to bring back defensive tackle Shamar Stephen, who started 20 games for the team from 2014-17 before posting two sacks in 14 starts for the Seahawks last year.

Representatives for defensive tackle Sheldon Richardson were free to talk to other teams Monday. The Vikings still rank near the bottom of the league in available cap space, meaning they will likely need to clear additional room to facilitate a serious run at Richardson or a prominent free agent.

Monday's moves left the Vikings with a total of $9.87 million in salary cap space, not counting Stephen's salary figure, before the start of the new league year Wednesday.

The offensive line figures to be at the top of the Vikings' to-do list; Remmers' release left the team with just one guard (Danny Isidora) who has played in an NFL regular-season game. Remmers' agent, Brett Tessler, tweeted the team talked to him about a restructured deal for the lineman before deciding to release him.

The Vikings also face decisions on backup quarterback Trevor Siemian and running back Latavius Murray — both scheduled to become free agents Wednesday — as well as defensive tackle Tom Johnson, guard Nick Easton and receiver Aldrick Robinson, among others.

Griffen, who is scheduled to make $10.9 million this season, would have his base salary guaranteed for the year if he is still on the roster by Friday. Griffen, who turns 32 in December, posted 5 ½ sacks last season, missing five games while dealing with mental health issues.

The Vikings would also fully guarantee Trae Waynes' $9.069 salary for 2019 if the cornerback is on the roster when the new league year starts at 3 p.m. Wednesday.

Tight end Kyle Rudolph told the Star Tribune on Sunday he has not been approached about restructuring his deal, but added he would be open to reducing his $7.625 million cap number for 2019 as part of a new deal that would add guaranteed money and additional years to his current contract, which expires after this season.

And if the Vikings were to complete a new deal with Adam Thielen that rewards the wide receiver for back-to-back Pro Bowl seasons, they could structure it in a way that slightly lowers Thielen's $8.1 million cap hit for 2019.

Staff writer Andrew Krammer contributed to this report.