The Eagles In Talks for Vegas Residency at The Sphere, Deal Not Locked

The Eagles might be stepping in to replace U2 as the Sphere's next big legacy act -- that is, if they can hammer out these negotiations they're currently involved in ... TMZ has learned.

Sources with direct knowledge tell us the iconic rock band are in active discussions right now to potentially serve as forthcoming talent to fill in at Sin City's newest music venue ... which would be a big deal, seeing how there's only been one so far in its big debut.

We're told that while The Eagles are in in talks at the moment, a deal isn't in place yet -- and it's unclear when exactly things might get finalized.

One thing we do know is the timeframe organizers have in mind for a would-be residency for Don Henley and co. assuming everything works out ... we're told they're thinking Fall/Winter.

That jibes with the Eagles' farewell tour they announced last year -- dubbed 'The Long Goodbye' -- which is supposed to kick off in September out in NYC. They have a number of shows scheduled all over the country, and those are supposed to run through mid-November.

Assuming this timeline ends up falling into place the way our sources say they might -- it would appear they'd be slated to start performing at the Sphere sometime around late November, and would probably keep on jamming out there for a few months.

Bono and the boys have been occupying the Sphere space since September, and their final shows are going down later this weekend ... marking about 4 months worth of music.

Of course, the reviews for the Sphere have been spectacular ... and people say it's truly one of those things you have to see to believe. Lots of cool visuals going on inside (and out).

One last thing ... the Eagles have been touring with a live orchestra lately -- and while it remains to be seen if something like that would manifest at the Sphere ... it's possible.

In terms of money, no word on how much the 'Hotel California' musicians would snag for something like this ... but U2 is said to have been raking in about $4 million a concert.