The franchise tag kept the Giants from potentially losing Saquon Barkley and changing the face of their franchise. 

As soon as quarterback Daniel Jones agreed to a new contract Tuesday, the Giants pivoted to tagging Barkley to keep the star running back from unrestricted free agency.

If the Giants had not re-signed Jones minutes before the 4 p.m. deadline to end tense negotiations, the tag instead would have gone to him, and Barkley would have been headed to the open market to determine his value with at least six teams expected to be in pursuit. 

There remains optimism that an extension could be completed before an NFL-imposed July 17 deadline shuts down talks for the length of the season, possibly as soon as over the five days before free agency opens.

A multiyear deal would free up even more salary-cap space for the Giants to improve the roster by lowering Barkley’s hit from the $10.1 million salary just added to the books. 

But Jones’ agreement freeing up the tag created a leverage swing.

Barkley turned down a multiyear extension averaging about $12.5 million per year in November.

That number increased slightly, according to league sources, as negotiations continued after the season.

Other holdups include the length of the deal (three or four years) and distribution schedule of guaranteed money. 

The Giants have an extension offer out to Barkley that he can accept, general manager Joe Schoen said last week, but it appears they drew a much firmer line in the sand with him than with Jones, even after the latter shot for the moon by asking for $48 million per year with his new agents, per sources.

Barkley and Schoen met briefly Monday. 

“I think [playing on the tag] would upset anybody,” Barkley told The Post after losing in the playoffs. 

Allowing Barkley, the No. 2 overall pick in the 2018 draft, to test free agency would’ve been unthinkable at one point.

He arrived with Hall of Fame-hype, and is a two-time Pro Bowler and a Walter Payton Man of the Year Award nominee.

The non-exclusive franchise tag used means another team could sign Barkley to an offer sheet, and the Giants would have the chance to match the deal or receive two first-round picks as compensation, which is extremely unlikely. 

Barkley does not have to immediately sign the tag and could choose to follow a common message-sending practice by not showing up for spring voluntary workouts.

That never has been Barkley’s way — propping up teammates when he was the lone bright spot amid years of losing, speaking with reverence about the Giants’ tradition and buying into all messaging — but team-first behaviors didn’t pay off at the negotiating table. 

Running backs accounted for three of the six franchise tags used around the league: Barkley, NFL rushing leader Josh Jacobs (Raiders) and Tony Pollard (Cowboys).

Miles Sanders (Eagles) now heads the class of free-agent running backs. Teams can remove an unsigned tag — a rarely employed move — if the process drags out. 

Barkley has earned $38.6 million over his first five seasons and looked headed for a big payday after rushing for a career-high 1,312 yards and 10 touchdowns in bouncing back from two injury-plagued seasons.

Success for him and Jones in a two-headed ground attack goes hand-in-hand. 

“Congrats brudda,” Barkley wrote on Twitter, along with Jones’ handle and raised fist and black heart emojis. 

After initially asking for money in line with top-paid running back Christian McCaffrey’s $16 million per year deal, Barkley lowered his price and acknowledged he wasn’t looking to “reset” the market because he wanted to be a “Giant for life.”

But belief around the league is Schoen belongs to the school of thought that salary cap space is better spent elsewhere, and the physical toll endured by running backs means a rotation of cheap options is the way to build a team. 

Extensions for Todd Gurley and Ezekiel Elliott didn’t work out for the Rams and Cowboys, respectively, but the past five running backs to receive extensions worth at least $12 million per year all had career-best rushing totals after signing.

Adjusted for salary-cap inflation since then, a comparable deal for Barkley averages about $14 million per year.