While most of Los Angeles basked in the possibilities of the Rams returning to the Southland to play NFL football again — this time at a new stadium on the site of the former Hollywood Park Race Track in Inglewood — the resolve and commitment at the Anschutz Entertainment Group offices in downtown Los Angeles remained surprisingly upbeat and positive Tuesday.

There is no doubt the St. Louis Rams owner’s announcement that he is joining forces with Hollywood Park developers to build an 80,000-seat football stadium could be a punishing blow to AEG’s grand plan to build Farmers Field adjacent to Staples Center.

Maybe even a knockout punch.

If Rams owner Stan Kroenke follows through on this plan and his franchise makes the move to Inglewood, it will mean Farmers Field falling by the wayside as so many other stadium proposals have over the past 20 years in Los Angeles.

It could be a demise that was inadvertently triggered by former AEG president Tim Leiweke, whose passion for Farmers Field was initially its greatest strength but eventually became part of its downfall.

Leiweke’s enthusiasm lifted Farmers Field off the ground and took it further than even AEG head Phil Anschutz ever believed possible.

In some ways, history will likely look back on Leiweke with gratitude for showing the NFL that the necessary political and financial resources can actually come together in Los Angeles to green-light a world-class football stadium.

In doing so, he helped put Los Angeles back on the NFL radar in a way it hadn’t been for years.

Ultimately, though, it was Leiweke’s overly ambitious and public negotiating tactics that turned off the NFL — which prefers to turn its business dealings on mute — while also creating some animosity within the offices of AEG.

Leiweke lost his job as a result, and Farmers Field fell off the tracks in the process.

It can be argued the project has never regained its footing since, despite the efforts of Anschutz to get it back on track.

In the meantime, other local stadium ideas began percolating.

Including the plan Kroenke rolled out to the world late Sunday night.

And while there is a feeling Kroenke and the Rams will eventually land in Inglewood, AEG is not giving up the fight just yet.

“The sense I’ve gotten the last two days is it’s still full bore ahead,” said a source at AEG.

That was after the statement AEG released Monday:

“We continue our efforts to advance Farmers Field and we remain confident in the advantages of our project over any of the other sites that have been rumored for a new football stadium. Farmers Field offers a highly desirable location at L.A. LIVE, billions in existing infrastructure and complimentary facilities surrounding the site, and a fully entitled project able to host two NFL franchises without the legal, political and taxpayer risk that other sites face.”

There are reasons to be hopeful, as fading as they might be.

The first is that Kroenke went off the ranch on this one, pulled an end-around on the NFL and brokered a deal independent of the league’s carefully crafted wishes.

And that the NFL will ultimately vote down Kroenke’s request for relocation, should it come to that.

But after talking to a high-ranking official Tuesday, it appears that isn’t the case.

In fact, the NFL appears on board with what Kroenke is doing.

The second is that Kroenke — and the NFL — is simply using the threat of Los Angeles to motivate St. Louis leaders into building a new stadium that will keep the Rams along the banks of the Mississippi River.

Or, as another NFL official told me: “This is a bidding war.”

And that would make Kroenke’s bombshell especially well timed.

Later this week, a St. Louis task force made up of former Anheuser-Busch president Dave Peacock and attorney Bob Blitz is expected to present Missouri Gov. Jay Nixon with a plan they believe will keep the Rams in St. Louis. Now more than ever, that plan needs to be foolproof.

Or else.

At least publicly, Peacock and Blitz remain confident.

“The news today is another reminder of how much competition there can be for National Football League franchises and projects that include NFL stadiums, but it does not change our timeline or approach,” Peacock and Blitz said in a statement. “It is important to remember this will be a long-term process, but one that the State of Missouri and the St. Louis region are fully pledged to seeing through.

“We are ready to demonstrate our commitment to keeping the NFL here, and to continue to illustrate why St. Louis has been and will always be a strong NFL market. We will present a plan to Governor Nixon this Friday as scheduled, and we expect that it will meet his criteria, thereby allowing us to share our vision with the public shortly thereafter. In the meantime, we will continue to have discussions with the NFL, as well as Rams leadership.”

Still, it seems Kroenke resorted to an especially hard-handed negotiating tactic if his plan really is to stay in St. Louis. No surprise, then, that some city leaders have drawn a line in the sand.

Jeff Rainford, spokesman for St. Louis Mayor Francis Slay, told reporters Monday that Slay doesn’t believe St. Louis should just hand the Rams the key to the city now that Los Angeles has come into the picture.

“A National Football League franchise does have value, and we should want one, but let’s use some common sense,” Rainford said. “The parameters are not a blank check.”

In fact, one wonders if Kroenke has poisoned the waters in jilted St. Louis to the point there is no going back. Can you imagine Rams fans opening their arms and wallets to a franchise that seemingly has its heart on being somewhere else?

And does the NFL really want that kind of public-relations nightmare on its hands moving forward — especially with all the other perception issues the league is dealing with?

The last hope for Farmers Field is the NFL stepping in to help broker a deal between AEG and either the San Diego Chargers or Oakland Raiders, who remain mired in uphill battles to build new local stadiums.

That remains a possibility, but with Kroenke making such a bold move it seems obvious the NFL is behind him.

All of which bodes well for the Rams adding Los Angeles back to their name.

Only they will be playing in Inglewood rather than downtown.

If so, Farmers Field will meet the same fate as so many other Los Angeles stadium plans over the past 20 years.