On your marks, get set … sign.

NFL free agency opens today at noon with a “legal tampering” period, when teams can officially begin negotiating with free agents and their representatives. Unofficially, agents and teams often engage in tampering days ahead of time, allowing for big deals to be struck as early as Monday afternoon.

The Patriots hold $82.79 million in cap space, second-most in the league, according to Over The Cap. The front office has already worked to retain a few of its top free agents, placing the transition tag on safety Kyle Dugger and re-signing tight end Hunter Henry to a long-term deal. Other players — offensive lineman Mike Onwenu and edge rusher Josh Uche — are expected to hit the open market.

Regardless of how many players the Patriots retain, the front office recognizes its roster needs an infusion of outside talent on both sides of the ball. Here are six things to watch for in free agency:

1. Where are the wide receivers?

All of the best wideouts are off the market, thanks to new extensions or the franchise tag.

That leaves Calvin Ridley as the only potential No. 1 receiver available, with Marquise Brown, Darnell Mooney and Gabriel Davis among the best No. 2s. The Patriots could sign multiple veterans, knowing they’re likely to follow a rookie quarterback into next season. The front office is also reportedly looking to offload veterans DeVante Parker and JuJu Smith-Schuster.

Smith-Schuster signed a 3-year, $25.5 million contract last year in free agency, a deal that should be surpassed by whichever receiver(s) the Patriots sign this spring.

2. Plan B at offensive tackle

New England Patriots guard Mike Onwenu (71) lines up against the Las Vegas Raiders during the first half of an NFL football game, Sunday, Dec. 18, 2022, in Las Vegas. (AP Photo/Rick Scuteri)

Onwenu is tracking to represent himself in free agency and is seeking offensive tackle money, per ESPN. That could lead to a deal worth $16 million to $18 million annually, a price the Patriots may not be willing to pay relative to other players on the market.

If so, and Onwenu, arguably their most important free agent, walks out, who replaces him?

Ex-Cowboys offensive tackle Tyron Smith feels like a long shot, given he’s at the ring-chasing stage of his career. Former Bengals first-round pick Jonah Williams can play both sides as a proven starter. Other names to watch include Mekhi Becton, Jermaine Eluemunor and Josh Jones — again, if Onwenu doesn’t re-sign.

3. Who’s the new QB?

In the wake of trading Mac Jones, the Patriots are reportedly aiming to sign a veteran quarterback.

Among the best available, Jacoby Brissett would fit like a glove.

Brissett understands his place in the league as a stop-gap starter who most teams view as an ideal backup. He enjoyed his best season under new Patriots offensive coordinator Alex Van Pelt in Cleveland. Brissett also started his career in New England, where his locker-room leadership would be a boon to new head coach Jerod Mayo.

Gardner Minshew, Joe Flacco and Tyrod Taylor are other veterans who could fit in a Patriots quarterbacks room that needs a veteran presence. Baker Mayfield, a higher-end option, re-signed with the Buccaneers on Sunday.

4. Trade talks

Speaking of Jones, the Patriots dealt their 25-year-old former starter for a sixth-round pick Sunday. They may not be done.

Armed with so much cap space, the Pats could use that room to absorb a high-priced veteran they otherwise may not be able to afford in a deal that allows another team to create cap flexibility. Or, as mentioned, Parker and Smith-Schuster could be headed out. Between the two, Parker is more likely to earn a late-round pick in return, while trading Smith-Schuster may require the Patriots to attach a draft pick to convince another front office to take on his contract.

The Chargers reportedly have talked to teams about trading some of their best players, including wide receivers Keenan Allen and Mike Williams and edge defenders Khalil Mack and Joey Bosa.

5. Burning cash?

Mayo said on WEEI shortly after he was hired as head coach that the Patriots were ready to “burn some cash” with so much cap space available this offseason. He later walked back those comments while speaking to MassLive, but it still would not be remotely surprising to see the Patriots in on some of the higher-priced free agents and to indeed “burn some cash” in the next few days.

The Patriots still have a ton of cap space, and they need to hit a minimum cash-spending floor over the next three years.

The team is realistic about where they stand with their current roster and knows they need help to get back to the postseason. They want to build through the draft, but it will take time to see those additions make dividends.

6. Darkhorse signing options

The most apparent needs on the Patriots’ roster are on offense at quarterback, wide receiver and offensive tackle. But don’t be shocked if they spend big on defense.

Their pass defense especially could be replenished with help at cornerback or with a pass-rushing option. Cornerback L’Jarius Sneed is available via trade after being franchised by the Chiefs. Dolphins free-agent defensive tackle Christian Wilkins is the top interior pass-rusher. The Eagles reportedly are shopping edge defenders Josh Sweat and Haason Reddick. The top free-agent edge defenders include Danielle Hunter (Vikings) and Bryce Huff (Jets).

The Patriots’ defense was among the league’s best units last season, but they were better against the run than defending the pass.