JACKSONVILLE, Fla. — Arik Armstead’s unemployment lasted roughly a day.

The Jacksonville Jaguars agreed to terms with the former San Francisco defensive tackle on a three-year, $51 million contract Thursday, a person with knowledge of the decision said. The person spoke on condition of anonymity because neither side had announced the move.

Armstead’s Career and New Role

The 49ers released Armstead to create salary cap space when the new league year began Wednesday. He will now switch coasts and reunite with Jaguars general manager Trent Baalke, who drafted Armstead with the 17th overall pick in 2015.

If he can stay healthy, Armstead should provide a huge addition for a team that ranked 25th in the league last season with 40 sacks. Armstead will be asked to line up between standout pass rushers Josh Allen and Travon Walker and provide the kind of middle push the team has been missing for years.

Impact of Ridley’s Move on Armstead’s Signing

The Jaguars wouldn’t have been in a position to land Armstead had they brought back receiver Calvin Ridley. But when Ridley agreed to sign with rival Tennessee on a four-year, $92 million deal Wednesday, the Jags had the flexibility to get the 6-foot-7, 290-pound defender.

Armstead had five sacks in 12 games in the regular season in 2023 and added one more in the playoffs. He has 33 1/2 sacks in 116 games in the regular season, and his eight career sacks in the postseason are the second most in Niners history.

Armstead’s Health and Financial Impact

The 30-year-old Armstead was hampered by injuries the past two seasons, playing only 21 regular-season games in that span because of injuries to his knee and foot. He played through a torn meniscus in his right knee in the postseason and had surgery after the Super Bowl.

Armstead was due a $17.4 million base salary this season and would have counted $28.4 million against the cap, leading the Niners to release him.