Frank Gore Mentoring Stud Bills Rookie Devin Singletary, Here's My Big Secret

Buffalo Bills rookie running back Devin Singletary says TWO legendary running backs have been giving him the secrets to success in the NFL ... and he's telling all to TMZ Sports.

After Devin balled out on Sunday -- 140 yards from scrimmage and a TD -- teammate Frank Gore brought over Adrian Peterson to give him some postgame love.

22-year-old Singletary -- a 3rd-round pick out of FAU -- says Peterson not only gave him career advice but offered to be a mentor. Devin tells us how the conversation went down, it's pretty cool.

In fact, we reached out to Peterson ... who told us he's made it his mission to help out young players to pass along the help he got when he first got to the league.

"I’m what [LaDainian Tomlinson] and Terrell Davis were to me," Peterson says, "The players I grew up watching and admiring."

But, the player who's clearly had the biggest impact on Singletary so far is his Bills teammate, Frank Gore ... who's taken the kid under his wing in a big way.

Singletary says Gore isn't only setting the BEST possible example when it comes to work ethic -- but has gone out of his way to help the rookie get better.

In other words, it ain't no Brett Favre, Aaron Rodgers situation in Buffalo -- Gore is trying to set Devin up for longterm success.