He talked the talk, but now 49ers safety Donte Whitner is walking the walk ... officially filing an application with the court to legally change his last name to "Hitner," TMZ has learned.
Donte has been talking about making the move ever since the NFL fined him $21k for an illegal hit on a Rams wide receiver earlier this season.
But now, we've learned ... on Tuesday, Whitner sent his attorney Larry Zukerman to file the official request at Probate Court of Cuyahoga County, Ohio.
In the doc, Donte explains that he wants to make the change because it will be beneficial to his career as a pro football player and in other business ventures.
As we previously reported, the process usually takes about 6 weeks before the name change is granted by a judge ... so, Whitner probably won't become Hitner until the end of November ... right around the time the 49ers play Washington, another team that should consider a name change.