Darren Waller says if Tim Tebow wants his advice on the tight end position ... he'd gladly give it -- telling TMZ Sports he's down to be a mentor of sorts for the new Jaguar!

"If he thinks he can learn from me," Waller said of Tebow, "then I'd love to help him and help make his transition smoother."

The Las Vegas Raiders superstar definitely knows a thing or two about what Tebow is going through ... you'll recall, Darren actually started his NFL career as a wide receiver before making the switch to TE.

And, while even Waller admits that's a far easier task than changing from QB to TE, he says he can still relate to Tim and help him out.