The Tampa Bay Buccaneers player is accused of leaving his Cane Corso, Jitterbug, on the side of a Florida road last month ... where it was later found tired, hungry and alone.

The Buccaneers have announced they're investigating the incident ... but in a lengthy statement Wednesday, Nunez-Roches says he had nothing to do with the abandonment.

"We would never abandon a dog," Nunez-Roches says. "We were expecting our first baby, so we thought it would be safer to have only smaller dogs in the house."

"Jitterbug is a Cane Corso, which is an Italian Mastiff and not a Pit Bull as was incorrectly reported, and we gave her to a family that wanted one. We have no idea how she ended up in an animal shelter, but we absolutely did not and would never abandon her or any other dog."

Nunez-Roches says the allegations caused him to receive so many violent threats ... he was forced to call the cops and physically change his address.

"We love and have taken care of dogs for years," Nunez-Roches says. "But, because a few overzealous people mistakenly assumed we had abandoned a dog that was no longer ours, we have received threats and had our reputations smeared in the media."

Nunez-Roches says the Tampa Police Department is now handling the case ... and he says he wants retractions from people who made the accusations against him.

"Hopefully the groups who falsely accused us ... realize their mistake and we can all go back to living normal lives and taking care of our dogs and other pets."

As for Jitterbug, the dog was adopted shortly after it was found in Florida ... and we're told it's doing well and is very happy in its new home.