SANTA CLARA >> The 49ers tiptoed into this offseason vowing to “reset” and “recalibrate” their approach to roster costs, as relayed by general manager John Lynch.

Temptations are about to get real as free agency begins. Negotiations open Monday and signings can become official Wednesday, including the 49ers’ trade of wide receiver Deebo Samuel to Washington.

Veterans are already cleared to land deals if they’ve been released, such as defensive end Joey Bosa (Los Angeles Chargers) and wide receiver Davante Adams (New York Jets).

Some 13 months ago, as the 49ers prepared for the Super Bowl, CEO Jed York commended coach Kyle Shanahan’s approach to their roster’s makeup.

“When we draft and do things in free agency, it’s generally on the defensive side of the ball,” York said. “We generally do not draft offensive players super high. We’re not doing a ton of stuff in free agency for offensive players. It is more that he’s focused on the defense, because he knows he’s going to spend more time on the offense.”

This free agency period, there’s no illusion that the 49ers defense needs everyone’s attention after last season’s emotionally draining 6-11 disaster. One signing could flip the mojo. Two could double that pleasure, including contract extensions for incumbent starters. Any positive vibe will be welcome and in stark contrast to the negative aura that engulfed last season’s NFC championship reign.

The 49ers have been through enough ups and downs to know not to hinge their next season’s fate on free agency. Any franchise worth its Lombardi Trophies is built on the draft, which won’t be until April 24-26 (in Green Bay, for those attending).

Here is what you need to know heading into this week’s marketplace:

When it begins

Business picks up officially Monday at 9 a.m., when teams are allowed to contact agents of free agents — after informal chats may have happened at locales such as last week’s NFL scouting combine in Indianapolis.

The 49ers were five hours into that negotiation window last year when news broke of defensive end Leonard Floyd agreeing to a two-year contract. In 2023, defensive tackle Javon Hargrave’s contract (four years, $84 million) went public just as negotiations were permitted; Hargrave is to be released Wednesday, only two seasons into his tenure.

Because the league year does not officially commence until 1 p.m. Wednesday, all deals are on preliminary until then, including Samuel’s trade to Washington for a fifth-round draft pick. Even if contracts are agreed upon and prematurely reported, they aren’t complete until a player is signed (and passes a physical), as the 49ers were reminded a year ago when linebacker Eric Kendricks reneged on his verbal commitment and defected to the Dallas Cowboys.

Which 49ers are available?

Five starters are poised to become unrestricted free agents: cornerback Charvarius Ward, linebacker Dre Greenlaw, left guard Aaron Banks, safety Talanoa Hufanga and Hargrave.

Also unrestricted are these reserves: offensive tackles Jaylon Moore and Charlie Heck; quarterbacks Brandon Allen and Josh Dobbs; running backs Elijah Mitchell and Patrick Taylor; wide receiver Chris Conley; tight end Eric Saubert; defensive tackles Kevin Givens and Khalil Davis; linebackers De’Vondre Campbell and Demetrius Flannigan-Fowles; safety Tashaun Gipson; punter Pat O’Donnell; and, cornerbacks Isaac Yiadom, Rock Ya-Sin and Nick McCloud. Guard Jon Feliciano has announced his retirement.

Running back Jordan Mason and linebacker Curtis Robinson are restricted free agents.

Names of top free agents

Here are the more renowned players hitting free agency:

Quarterback: Aaron Rodgers, Sam Darnold, Russell Wilson, Daniel Jones, Jameis Winston, Joe Flacco, Justin Fields, Trey Lance, Zach Wilson, Mac Jones, Jimmy Garoppolo, Carson Wentz, Jacoby Brissett, Marcus Mariota, Drew Lock, Nick Mullens, C.J. Beathard

Running back: Aaron Jones, Najee Harris, Jamaal Williams, Nick Chubb, Raheem Mostert, Jeff Wilson Jr., JaMycal Hasty

Wide receiver: Davante Adams, Keenan Allen, Chris Godwin, Amari Cooper, Stefon Diggs, Tyler Lockett, DeAndre Hopkins, Mike Williams, Diontae Johnson, Robert Woods, D.J. Chark, K.J. Osborn

Tight end: Evan Engram, Zach Ertz, Austin Hooper, Tyler Conklin, Juwan Johnson, Gerald Everett, Durham Smythe, Ross Dwelley, MyCole Pruitt

Offensive line: Cam Robinson (T), Brandon Scherff (G), Drew Dalman (C), Ronnie Stanley (T), Tyron Smith (T), Joseph Noteboom (T), Patrick Mekari (T), Jedrick Wills (T), D.J. Humphries (T), Dalton Risner (G), Laken Tomlinson (G), Will Hernandez (G)

Defensive end: Joey Bosa, Khalil Mack, Josh Sweat, Haason Reddick, Demarcus Lawrence, Chase Young, Preston Smith, Matt Judon, Charles Omenihu, Clelin Ferrell, Dayo Odeyingbo

Defensive tackle: Jonathan Allen, Milton Williams, D.J. Jones, Dre’Mont Jones, Sheldon Rankins, B.J. Hill, Jarran Reed, Javon Kinlaw, Solomon Thomas

Linebacker: Shaq Thompson, Nick Bolton, Kyzir White, Lavonte David, Ernest Jones, Jerome Baker, Jamien Sherwood

Cornerback: D.J. Reid, Carlton Davis, Darius Slay, Byron Murphy, Rasul Douglas, Jonathan Jones, Asante Samuel Jr.

Safety: Jevon Holland, Camryn Bynum, Justin Reid, Harrison Smith, Tre’Von Moehrig, Jeremy Chinn, Justin Simmons, Elijah Molden, Andre Cisco

Who’s on the trade market?

The 49ers have not disputed the notion they could deal wide receiver Brandon Aiyuk, even though he’s four months into knee reconstruction recovery and six months into a rich contract (four years, $120 million).

These players also could be on the trade market: defensive ends Myles Garrett (Browns) and Trey Hendrickson (Bengals); wide receiver D.K. Metcalf (Seahawks) and Cooper Kupp (Rams); and, quarterbacks Kirk Cousins (Falcons) and Derek Carr (Saints).

Don’t rule out franchise-tagged free agents: wide receiver Tee Higgins (Bengals) and guard Trey Smith (Chiefs).

How are the finances?

The 49ers have just less than $35 million salary cap space, according to OverTheCap.com. The NFL’s salary cap climbed almost $24 million to $279.2 million.

Not factored into the 49ers’ current space: expected extensions for Brock Purdy and George Kittle, and possibly Fred Warner.