How big of a bet did Giants general manager Dave Gettleman place on Duke quarterback Daniel Jones?

The easiest way to quantify it is to look at salary cap space.

By drafting Jones at No. 6 instead of trading for demoted Josh Rosen of the Cardinals, the Giants committed tens of millions more to the quarterback position than they otherwise would have by taking a bargain.

Jones’ four-year contract is expected to be valued at $25.57 million, according at Spotrac.com. That includes a $4.65 million cap hit in 2019.

As the No. 10 pick in the 2018 NFL Draft, Rosen signed a four-year contract worth $17.59 million.

But it’s not an apples-to-apples comparison. The savings would have been bigger. Let us explain.

Because signing bonuses are the salary cap responsibility of the team dealing away a player, the Cardinals will have to suffer the full hit of Rosen’s bonus if/when he is traded to make room for 2019 No. 1 overall pick Kyler Murray as the starter. That number is $10.8 million, accelerated into their 2019 cap.

The team that trades for Rosen is on the hook for the remaining about $6.23 million in guaranteed salary through 2021, about $2.1 million per year. In other words, NFL peanuts.

So, the Giants opted to commit $25.57 million over four years to Jones rather than $6.23 million over three years to Rosen, who most analysts think is a better pro prospect even after an underwhelming rookie season.

NFL Draft selections are slotted into a rookie wage scale, and the amount of money decreases with each successive pick from No. 1-254. All the money on a first-round pick’s contract is guaranteed, and most of it is attached to a signing bonus with very little room to negotiate.

It does not vary by position, so a No. 6 quarterback gets the same day as a No. 6 kicker (if such a thing existed).

In a world of $140 million contracts for Russell Wilson and $23.2 million salary cap hits for Eli Manning, relatively cheap quarterback contracts are a premium asset. It’s one of the reasons the Giants were criticized for passing on Sam Darnold, Josh Allen and Rosen for running back Saquon Barkley in last year’s draft.

Jones still is a bargain compared to the contracts of veteran quarterbacks.

If the Giants traded for Rosen — giving up a second-round pick was the most likely scenario — they still would have paid another player at No. 6 the same contract now being given to Jones.

In that scenario, Rosen’s money would take the place of the No. 37 pick and it would have been close to a salary cap wash. The Giants ended up trading their second-round pick anyway to move up and take cornerback Deandre Baker at the end of the first round.

The No. 17 pick (defensive tackle Dexter Lawrence) is due $13.16 million with a $2.39 million cap hit in 2019, but the Giants didn’t want to risk waiting until then to draft Jones for fear he would be drafted elsewhere.

The Giants entered the NFL Draft with $14.55 million in salary cap space, according to NFLPA records, after converting $7.5M of guard Kevin Zeitler’s base salary into a bonus to create an addition $5 million in room.

If the Giants had used all 12 of their draft picks, they would have eaten up about $7.85 million in cap space, according to overthecap.com’s formula. The only have 10 picks now, seven remaining.

Like any first-round pick, Rosen and Jones can have a fifth-year of team control added to their first contract if an option is picked up.

Ryan Dunleavy may be reached at rdunleavy@njadvancemedia.com. Follow him on Twitter @rydunleavy. Find our Giants coverage on Facebook.