Fact: David Carr was the most sacked rookie QB in the history of the NFL ... 76 sacks in 2002!
Fact: He was so determined to make sure his little bro, Derek Carr, didn't suffer the same fate, he personally ran him through an anti-sack clinic back in college!
We spoke with Tim DeRuyter -- Derek's old ball coach at Fresno State who says David would spend hours with the future Raiders QB ... giving him all the tips he needed to avoid eating turf at the next level.
Tim says NFL scouts were concerned that Derek could be sack-prone like David -- so David made it his mission to prove them all wrong!
Seems the clinic worked ... Derek's been killing it this season with more than 3,000 yards and 22 TDs through 11 games ... and he's only been sacked 13 times.