Dak Prescott Begins Construction on New Texas Mansion

Dak Prescott has begun rebuilding in Texas ... TMZ Sports has learned construction on his new mansion in Prosper is now underway.

Check out these photos we obtained on Monday ... you can see multiple structures have been erected on the Prescott property that used to feature a multi-million-dollar house.

The Dallas Cowboys quarterback, of course, knocked it down back in October ... with the hopes of putting a more modern pad in its stead. And, as you can see, QB1's dream is clearly on its way to becoming a reality.

So far, at least one barn-like building has been put up ... while another has been framed out some 20-or-so yards away. Several steel beams have been placed into the ground, too, suggesting even more living space is about to be cropping up in the near future.

Prescott could certainly use the room -- his fiancée, Sarah Jane, just gave birth to their second child late last month.

As for any unforeseen expenses that pop up in the building process -- Prescott can afford those ... he's currently in the middle of a contract that's paying him $60 million per year.