The MLB legend and his supermodel wife, Hannah Jeter, had listed the place for $29 million back in September -- and according to the realtors in charge of the deal, there was major interest in the place.

Jeter ultimately agreed to sell for roughly $22.5 million -- which the real estate company, Smith & Associates, says is the most expensive home purchase ever in Tampa Bay.

We know what you're thinking ... who bought it?!

So far, the buyer has not been revealed -- but we're told it's NOT Tom Brady and Gisele.

Our Tampa sources tell us they recently moved out of the place and are living nearby while they're building a brand new pad in the exclusive Indian Creek Island community in Miami.

As for Jeter, he bought the 22,000 square-foot estate back in 2005 -- reportedly planning to put down $2.3 million. But, after he bought it, there was a major renovation and the final product is one of the sickest properties we've ever seen.

We're talking 7 bedrooms, 8 full bathrooms plus 8 half-baths (so, 16 total toilets if you're keeping score) ... along with an 80-foot saltwater lap pool, a gym, wine cellar AND a movie theater!

There's also a 6-car garage -- and the place comes with its own private dock with 2 boat lifts!!

Smith & Associates says they did deep background searches on all interested parties before they were allowed to check out the property ... in an effort to make sure only serious buyers were allowed on site.

Jeter moved to Miami a while back -- which is why he was able to rent it to TB12 after the QB signed with the Tampa Bay Bucs.

Tom reportedly loved the place and even held some private workouts in the yard.