Michigan head coach Jim Harbaugh is urging the NFL and NCAA to amend their rules and provide more flexibility to college football players who consider making the jump to the next level despite having college eligibility left.

In an open letter Thursday, Harbaugh laid out a proposal that would allow football players to enter the NFL Draft at any point during their collegiate careers. He also wants players who go undrafted to be allowed to return to their respective schools.

Current NFL rules require that a player must be at least three years removed from high school before entering the draft. NCAA rules state that college football players aren’t allowed to return to school once they declare for the draft, even if they have eligibility remaining.

“There are ‘early bloomers’ capable of competing in the NFL and earning a livelihood at an earlier age,” Harbaugh wrote in the letter. “The goal would be to create a scenario that makes adjustments for all current and future student-athletes that puts the timeline for transition to professional football at their discretion and that of their family.

“I propose an option that allows them to make the decision that is best for them.”

Harbaugh also said he would like to see rules that allow college football players to receive advice from agents before signing professional contracts, as long as the student-athlete isn’t compensated during that process.

Under Harbaugh’s plan, a player would be permitted to enter his name in the draft and return to school if he isn’t selected in the seven rounds of the draft. If a player is picked in the draft or signs a free-agent deal, he would forfeit the remainder of his college eligibility.

Harbaugh’s letter also proposed eliminating the redshirt, giving all players five years of eligibility and lifting the hard cap of 25 incoming scholarship recruits and transfers.