By Scott Malone

BOSTON (Reuters) - New England Patriots quarterback Tom Brady on Friday said he would end his legal battle against the National Football League over the decision to suspend him for four games as a result of the "Deflategate" scandal.

"It has been a challenging 18 months and I have made the difficult decision to no longer proceed with the legal process," the star player said in a statement posted to his official Facebook page. "I look forward to having the opportunity to return to the field this fall."

On Wednesday, the 2nd U.S. Circuit Court of Appeals in New York declined to review its April decision to reinstate the suspension of Brady, 38, who was twice the league's most valuable player.

Brady was suspended after the NFL discovered underinflated footballs were used in the Patriots' 45-7 rout of the Indianapolis Colts in the January 2015 American Football Conference championship game.

The win propelled the Patriots to Super Bowl XLIX, where they beat the Seattle Seahawks, giving Brady his fourth Super Bowl title.

The saga had become a major distraction for the NFL, which also faces criticism over player safety and the link between football and concussions.

"The penalty imposed by the NFL was unprecedented, unjust and unreasonable," Patriots owner Robert Kraft said in a statement on Friday. "What Tom has had to endure throughout this 18-month ordeal has been, in my opinion, as far removed from due process as you could ever expect in this country."

The NFL declined to comment, spokesman Brian McCarthy said in an e-mail.

The union that represents NFL players said it supported Brady's decision.

"We will continue to review all of our options and we reserve our rights to petition for cert to the Supreme Court," The NFL Players' Association said.

The nation's top court, currently operating with just eight of nine seats filled, reviews a small fraction of cases brought to it.

Even Boston's daily newspapers, which obsessively cover every step of the beloved quarterback, had been skeptical he would get a hearing from the Supreme Court.

"America has an unhealthy obsession with football," wrote Boston Globe sports columnist Christopher Gasper following Wednesday's 2nd Circuit decision. "An institution that deals with weighty issues that affect the lives of millions, such as marriage equality, reproductive rights, and campaign finance, is now going to intervene in a power struggle between millionaires and billionaires over who gets to play in football games? No thanks."

(Additional reporting by Frank Pingue in Toronto; Editing by James Dalgleish and Jonathan Oatis)